Alert archive / California / Flash Flood Watches in 2017
Flash Flood Watch 6, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this flash flood watch at Feb 8, 2017, 9:18 AM PST for 7 counties in California. It took effect at Feb 9, 2017, 4:00 AM PST. It was in force for 22 hr.
The area
The counties it named.
The facts
- Issued
- Feb 8, 2017, 9:18 AM PST (17:18 UTC)
- In effect from
- Feb 9, 2017, 4:00 AM PST
- Expired
- Feb 10, 2017, 1:51 AM PST
- In force
- 22 hr
- Issued by
- NWS San Francisco Bay Area, CA
- Flood severity
- None
Counties Marin County, CA, Monterey County, CA, Napa County, CA, San Mateo County, CA, Santa Clara County, CA, Santa Cruz County, CA, Sonoma County, CA
The radar
The San Francisco radar (KMUX), 53 km from the middle of the area, began a volume at 17:18 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Oakland, CA (KOAK), launched 12:00Z, 5.3 hours before the alert went out and 17 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 621 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 175 m²/s²
- 0-3 km storm-relative helicity
- 339 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
The text
As transmitted.
899 WGUS66 KMTR 081718 FFAMTR URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service San Francisco Bay Area 918 AM PST Wed Feb 8 2017 ...ANOTHER POTENT WEATHER SYSTEM WILL BRING WIDESPREAD RAINFALL AND POTENTIAL FLOODING TO THE REGION ON THURSDAY... CAZ505>507-090500- /O.NEW.KMTR.FF.A.0006.170209T1200Z-170210T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- Including the cities of...Tamalpais-Homestead...Sausalito... Santa Rosa...South Santa Rosa...Napa...San Rafael...Petaluma... Novato...Rohnert Park...Angwin...Lagunitas-Forest Knolls... Woodacre 918 AM PST Wed Feb 8 2017 ...FLASH FLOOD WATCH IN EFFECT FROM LATE TONIGHT THROUGH THURSDAY EVENING... The National Weather Service in San Francisco has issued a * Flash Flood Watch for a portion of western California... including the following areas...Coastal North Bay Including Point Reyes National Seashore...North Bay Interior Valleys and North Bay Mountains. * From late tonight through Thursday evening * A period of moderate to locally heavy rain is expected across the North Bay on Thursday as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 4 inches are forecast in these areas through Thursday evening. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage, rapid rises on streams and creeks with some likely exceeding bankfull, some river flooding and potential rock and mud slides. * Travel may become very difficult at times. Some roadways may be flooded or impassable. Never drive into unknown depths of water! Turn around, don't drown. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ CAZ509-512-517-529-090500- /O.NEW.KMTR.FF.A.0006.170209T1200Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ San Francisco Peninsula Coast-Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Northern Monterey Bay- Including the cities of...Pacifica...Scotts Valley... Boulder Creek...Day Valley...Santa Cruz...Watsonville...Live Oak 918 AM PST Wed Feb 8 2017 ...FLASH FLOOD WATCH IN EFFECT FROM LATE TONIGHT THROUGH FRIDAY MORNING... The National Weather Service in San Francisco has issued a * Flash Flood Watch for a portion of western California... including the following areas...Northern Monterey Bay...San Francisco Peninsula Coast...Santa Cruz Mountains and Santa Lucia Mountains and Los Padres National Forest. * From late tonight through Friday morning * A period of moderate to locally heavy rain is expected along the coastal ranges of the Central Coast on Thursday as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 3 inches are forecast in these areas through Thursday night. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage, rapid rises on streams and creeks with some likely exceeding bankfull, some river flooding and potential rock and mud slides. Recent burn scars will also be susceptible to debris flows during periods of intense rainfall. * Travel may become very difficult at times. Some roadways may be flooded or impassable. Never drive into unknown depths of water! Turn around, don't drown. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
5 follow-up statements
268 WGUS66 KMTR 090452 FFAMTR Flood Watch National Weather Service San Francisco Bay Area 852 PM PST Wed Feb 8 2017 ...ANOTHER POTENT WEATHER SYSTEM WILL BRING WIDESPREAD RAINFALL AND POTENTIAL FLOODING TO THE REGION ON THURSDAY... CAZ505>507-091300- /O.CON.KMTR.FF.A.0006.170209T1200Z-170210T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- Including the cities of...Tamalpais-Homestead...Sausalito... Santa Rosa...South Santa Rosa...Napa...San Rafael...Petaluma... Novato...Rohnert Park...Angwin...Lagunitas-Forest Knolls... Woodacre 852 PM PST Wed Feb 8 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 4 AM PST THURSDAY THROUGH THURSDAY EVENING... The Flash Flood Watch continues for * A portion of western California...including the following areas...Coastal North Bay Including Point Reyes National Seashore...North Bay Interior Valleys and North Bay Mountains. * From 4 AM PST Thursday through Thursday evening * A period of moderate to locally heavy rain is expected across the North Bay on Thursday as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 4 inches are forecast in these areas through Thursday evening. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage, rapid rises on streams and creeks with some likely exceeding bankfull, some river flooding and potential rock and mud slides. * Travel may become very difficult at times. Some roadways may be flooded or impassable. Never drive into unknown depths of water! Turn around, don't drown. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ CAZ509-512-517-529-091300- /O.CON.KMTR.FF.A.0006.170209T1200Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ San Francisco Peninsula Coast-Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Northern Monterey Bay- Including the cities of...Pacifica...Scotts Valley... Boulder Creek...Day Valley...Santa Cruz...Watsonville...Live Oak 852 PM PST Wed Feb 8 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 4 AM PST THURSDAY THROUGH FRIDAY MORNING... The Flash Flood Watch continues for * A portion of western California...including the following areas...Northern Monterey Bay...San Francisco Peninsula Coast...Santa Cruz Mountains and Santa Lucia Mountains and Los Padres National Forest. * From 4 AM PST Thursday through Friday morning * A period of moderate to locally heavy rain is expected along the coastal ranges of the Central Coast on Thursday as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 3 inches are forecast in these areas through Thursday night. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage, rapid rises on streams and creeks with some likely exceeding bankfull, some river flooding and potential rock and mud slides. Recent burn scars will also be susceptible to debris flows during periods of intense rainfall. * Travel may become very difficult at times. Some roadways may be flooded or impassable. Never drive into unknown depths of water! Turn around, don't drown. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
120 WGUS66 KMTR 091217 FFAMTR Flood Watch National Weather Service San Francisco Bay Area 417 AM PST Thu Feb 9 2017 ...ANOTHER POTENT WEATHER SYSTEM WILL BRING WIDESPREAD RAINFALL AND POTENTIAL FLOODING TO THE REGION ON THURSDAY... CAZ505>507-092000- /O.CON.KMTR.FF.A.0006.000000T0000Z-170210T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- Including the cities of...Tamalpais-Homestead...Sausalito... Santa Rosa...South Santa Rosa...Napa...San Rafael...Petaluma... Novato...Rohnert Park...Angwin...Lagunitas-Forest Knolls... Woodacre 417 AM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING... The Flash Flood Watch continues for * A portion of western California...including the following areas...Coastal North Bay Including Point Reyes National Seashore...North Bay Interior Valleys and North Bay Mountains. * Through this evening * A period of moderate to locally heavy rain is expected across the North Bay on Thursday as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 4 inches are forecast in these areas through Thursday evening. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage...apid rises on streams and creeks with some likely exceeding bankfull... some river flooding and potential rock and mud slides. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ CAZ509-512-517-529-092000- /O.CON.KMTR.FF.A.0006.000000T0000Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ San Francisco Peninsula Coast-Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Northern Monterey Bay- Including the cities of...Pacifica...Scotts Valley... Boulder Creek...Day Valley...Santa Cruz...Watsonville...Live Oak 417 AM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY MORNING... The Flash Flood Watch continues for * A portion of western California...including the following areas...Northern Monterey Bay...San Francisco Peninsula Coast...Santa Cruz Mountains and Santa Lucia Mountains and Los Padres National Forest. * Through Friday morning * A period of moderate to locally heavy rain is expected along the coastal ranges of the Central Coast on Thursday as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 3 inches are forecast in these areas through Thursday night. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage...apid rises on streams and creeks with some likely exceeding bankfull... some river flooding and potential rock and mud slides. Recent burn scars will also be susceptible to debris flows during periods of intense rainfall. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
259 WGUS66 KMTR 092004 FFAMTR Flood Watch National Weather Service San Francisco Bay Area 1204 PM PST Thu Feb 9 2017 ...ANOTHER POTENT WEATHER SYSTEM WILL CONTINUE TO RESULT IN WIDESPREAD RAINFALL AND POTENTIAL FLOODING ACROSS THE REGION TODAY... CAZ505>507-100600- /O.CON.KMTR.FF.A.0006.000000T0000Z-170210T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- Including the cities of...Tamalpais-Homestead...Sausalito... Santa Rosa...South Santa Rosa...Napa...San Rafael...Petaluma... Novato...Rohnert Park...Angwin...Lagunitas-Forest Knolls... Woodacre 1204 PM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 10 PM PST THIS EVENING... The Flash Flood Watch continues for * A portion of western California...including the following areas...Coastal North Bay Including Point Reyes National Seashore...North Bay Interior Valleys and North Bay Mountains. * Until 10 PM PST this evening * A period of moderate to locally heavy rain is expected across the North Bay today as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 1 to 2 inches are forecast in these areas through this evening. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage, rapid rises on streams and creeks with some likely exceeding bankfull, some river flooding and potential rock and mud slides. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ CAZ509-512-517-529-100600- /O.CON.KMTR.FF.A.0006.000000T0000Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ San Francisco Peninsula Coast-Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Northern Monterey Bay- Including the cities of...Pacifica...Scotts Valley... Boulder Creek...Day Valley...Santa Cruz...Watsonville...Live Oak 1204 PM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY MORNING... The Flash Flood Watch continues for * A portion of western California...including the following areas...Northern Monterey Bay...San Francisco Peninsula Coast...Santa Cruz Mountains and Santa Lucia Mountains and Los Padres National Forest. * Through Friday morning * A period of moderate to locally heavy rain is expected along the coastal ranges of the Central Coast today as a strong cold front pushes inland. The combination of saturated soils and recent heavy rainfall will result in excessive runoff into area streams and rivers as well as localized flash flooding. Additional rainfall amounts of 2 to 3 inches are forecast in these areas through tonight. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage, rapid rises on streams and creeks with some likely exceeding bankfull, some river flooding and potential rock and mud slides. Recent burn scars will also be susceptible to debris flows during periods of intense rainfall. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
918 WGUS66 KMTR 100558 FFAMTR Flood Watch National Weather Service San Francisco Bay Area 958 PM PST Thu Feb 9 2017 CAZ509-512-529-100700- /O.CAN.KMTR.FF.A.0006.000000T0000Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ San Francisco Peninsula Coast-Santa Cruz Mountains- Northern Monterey Bay- Including the cities of...Pacifica...Scotts Valley... Boulder Creek...Day Valley...Santa Cruz...Watsonville...Live Oak 958 PM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH IS CANCELLED... The Flash Flood Watch for the San Francisco Peninsula Coast, Santa Cruz Mountains, and Northern Monterey Bay has been cancelled. Widespread rainfall has ended across the region and stream gages indicate that most streams and creeks have peaked and have begun to recede. Scattered showers will continue overnight, but additional rises on streams and creeks is not anticipated. Continue to heed all road closures. Standing water in poorly drained areas may take several hours to recede. Mudslides and debris flows will continue to be possible. $$ CAZ505>507-100700- /O.EXP.KMTR.FF.A.0006.000000T0000Z-170210T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- Including the cities of...Tamalpais-Homestead...Sausalito... Santa Rosa...South Santa Rosa...Napa...San Rafael...Petaluma... Novato...Rohnert Park...Angwin...Lagunitas-Forest Knolls... Woodacre 958 PM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH WILL EXPIRE AT 10 PM PST THIS EVENING... The Flash Flood Watch for the North Bay will expire at 10 PM PST this evening. Widespread rainfall ended several hours ago and most small rivers and creeks have peaked and have begun to recede. Only scattered showers are expected overnight. Continue to heed all road closures. Standing water in poorly drained areas may take several hours to recede. Mudslides and debris flows will continue to be possible. $$ CAZ517-101500- /O.CON.KMTR.FF.A.0006.000000T0000Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Santa Lucia Mountains and Los Padres National Forest- 958 PM PST Thu Feb 9 2017 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 7 AM PST FRIDAY... The Flash Flood Watch continues for * A portion of western California...including the following area...Santa Lucia Mountains and Los Padres National Forest. * Until 7 AM PST Friday * A band of light to moderate rainfall remained over the Santa Lucia Mountains on Thursday evening as a cold front moved slowly south through the region. Rainfall since late Thursday afternoon has caused water levels on smaller rivers and streams in the area to rise on Thursday evening. Continued rainfall overnight may lead to flash flooding or debris flows. * The primary impacts will be localized ponding of water on low lying roadways with poor drainage...continued rises on streams and creeks with some possibly exceeding bankfull...and potential rock and mud slides. Recent burn scars will also be susceptible to debris flows during periods of heavier rainfall. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
978 WGUS66 KMTR 100951 FFAMTR Flood Watch National Weather Service San Francisco Bay Area 151 AM PST Fri Feb 10 2017 CAZ517-101100- /O.CAN.KMTR.FF.A.0006.000000T0000Z-170210T1500Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Santa Lucia Mountains and Los Padres National Forest- 151 AM PST Fri Feb 10 2017 ...FLASH FLOOD WATCH IS CANCELLED... The Flash Flood Watch for the Santa Lucia Mountains of the Los Padres National Forest in California has been cancelled. Steady rain associated with the frontal band is shifting south and east of the region and will taper to showers through the rest of the overnight hours. Area rivers and stream are generally cresting and or beginning to slowly recede. The threat of flash flooding has ended therefore the flash flood watch is being cancelled. Continue to adhere to any road closures and remember to never drive through standing water, especially at night when you cant see how deep it is. Showers will linger today into tonight but then dry weather is forecast Saturday through Wednesday before the next chance of significant rain returns by next Thursday. $$
What forecasters said that day
The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this flash flood watch went out at Feb 8, 4:17 AM PST, 5 hours 1 minute earlier.
Area forecast discussion, Feb 8, 4:17 AM PST, 5 hours 1 minute before
Area Forecast Discussion
National Weather Service San Francisco Bay Area
417 AM PST Wed Feb 8 2017
.SYNOPSIS...Scattered showers will continue around the Bay Area
today with locally moderate rainfall over the North Bay. Another
cold front will pass over the Bay Area late Thursday into early
Friday morning. Very gusty winds will develop ahead of the cold
front early Thursday and peak Thursday afternoon. The passing
cold front will also bring another round of moderate to locally
heavy rainfall. A few lingering showers will be possible on
Friday, but dry weather will return by the weekend with high
pressure.
&&
.DISCUSSION...as of 3:36 AM PST Wednesday...Per KMUX radar
imagery and Bay Area gages, scattered showers continue with a very
moist sub-tropical zonal flow. Satellite imagery indicates a
moisture plume of 1.1-1.25 inches over the region. Rainfall
overnight has been a few hundredths up to around one half inch of
rain. Regarding flooding, compared to Tuesday concerns are much
less any many gages indicate a downward trend. However, minor
flooding is still possible through early this morning.
For the rest of today, showers will continue to decrease in
coverage and intensity through early this morning. Latest
HRRR/WRF models show this brief respite, but another moisture push
is forecast after 15-18Z this morning with a 30-40kt jet at 850mb.
Therefore, do expect an increase in precip this afternoon, most
notably over the North Bay.
Of greater concern is the next frontal boundary/storm system that
is forecast for Wednesday night through early Friday.
Model consensus brings the cold front just off the NorCal coast by
12Z Thursday and then moving it inland during the day. Ahead of
the front southerly winds will increase Wednesday night and
eventually peak during the day Thursday with the actual fropa. Hi-
res models indicate some rather gusty winds over the entire North
Bay and the East Bay Hills/Santa Cruz Mountains. SW winds of 15 to
30 with gusts 45-50 mph will be possible. Would not be surprised
to see a few of the highest peaks hit 60 mph. A wind advisory has
been issued to account for the gusty winds and high potential for
downed trees due to wet soils. As for precip, rain will develop
over the North Bay early Thursday morning then increase in
intensity and coverage as the front moves southward during the
day Thursday. If the model guidance is correct this next system
could be even juicier moisture wise as it has a decent tropical
connection. This atmospheric river is a classic pineapple express
with a moisture tap all the way back to near HI. PWAT values
exceed 1.30 inches on the GFS and NAM for Thursday, which would be
higher than the last system. Combine the high PWATs with decent
orographic lift there will likely be some decent rainfall amounts
over the hills. Generally speaking, rainfall amounts of 1.25" to
3.00" for the North Bay and coastal ranges. There could be a few
jackpot locations up to 5.00" over the Santa Cruz/Santa Lucia Mts
if the moisture tap is fully realized. Urban areas and inland rain
shadowed areas will be 0.25" to 1.25". The biggest take away
message is that the Bay Area is not out of the woods yet and our
guard should not come down. Given all the recent rain and
flooding problems, any additional rainfall will only exacerbate
the situation, especially with the potential for moderate to heavy
rain. Flood watches will likely be needed with the next 12-24
hours. Lingering showers will be possible through Friday behind
the departing cold front. Enough cold air aloft will lower snow
levels that mixed precip/snow will be possible over the highest
peaks in Monterey county. Additionally, the cold air aloft will
help to destabilize the atmosphere leading to thunderstorms. This
scenario seems more likely over the Central Valley and have not
included any mention for the Bay Area.
Any remaining showers will end Friday night as high pressure
begins to build in from the north. Warm and dry weather is
expected on Saturday with lots of sunshine. The clear skies will
lead to some chilly overnight low with patchy frost possible
across the protected interior valleys Sunday morning. Dry weather
conditions along with seasonable temperatures are then likely
through the first half of next week. Longer range models then
indicate the potential for unsettled conditions to again return to
the region by late next week.
&&
.AVIATION...As of 4:12 AM PST Wednesday...For 12z Tafs. A very
complicated forecast over the next 24-36 hours, especially with
ceilings and visibilities. Latest observations across the region
show a mixed bag of CIGs from VFR to IFR. Current thinking at this
time is there will be intervals of off-and-on showers through the
morning at all terminals. By 20z, showers will be confined to the
North Bay and areas of the SF Bay Area. North Bay terminals will
likely be in MVFR/IFR for most of the day, whereas SF Bay
terminals will be VFR/MVFR through the day, possibly all VFR by
00z. South to southeasterly winds will be moderate for most areas
through the day. Winds become gusty by early Thursday morning as a
cold front approaches from the northwest. FROPA is expected
sometime between 22z Thursday and 02z Friday. Low confidence on
CIGs and timing. Moderate confidence on winds.
Vicinity of KSFO...VCSH and SHRA through the day. Intervals of
MVFR and VFR for KSFO, KOAK, and KSJC, then VFR by 00z. KSTS will
likely be IFR/MVFR majority of the day. Low confidence on CIGs and
timing. Southeast winds around 10 kt today, perhaps gusts at KSJC
and KOAK up to 20 kt at times in the afternoon. Moderate
confidence on winds.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Mainly VFR CIGs today, but could have
VIS drop to MVFR, especially with haze or any shower that occurs
this morning. Breezy southeast winds at KSNS, around 10-15 kt,
possibly gusting to around 25 kt this afternoon. Only light to
moderate southerly winds expected at KMRY.
&&
.MARINE...as of 03:40 AM PST Wednesday...South to southeast winds
will increase through the day Wednesday, with winds being the
strongest on Thursday, as a storm system approaches the area.
Winds will gradually decrease behind a cold front that is
forecast to move through the coastal waters Thursday evening. In
addition, hazardous sea conditions will continue today and likely
through the rest of the week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...SCA...Mry Bay
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
&&
PUBLIC FORECAST: MM
AVIATION: BAM
MARINE: BAM
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www.youtube.com/nwsbayareaHazardous weather outlook, Feb 8, 5:28 AM PST, 3 hours 50 minutes before
Hazardous Weather Outlook National Weather Service San Francisco Bay Area 528 AM PST Wed Feb 8 2017 CAZ006-505>507-511-512-091400- San Francisco- Coastal North Bay Including Point Reyes National Seashore- North Bay Interior Valleys-North Bay Mountains- East Bay Hills and the Diablo Range-Santa Cruz Mountains- 528 AM PST Wed Feb 8 2017 This Hazardous Weather Outlook is for portions of Northern California. .DAY ONE...Today and Tonight Light to occasionally moderate rainfall will continue to impact the region tonight. However, widespread heavy rainfall is not anticipated. Southerly winds will increase tonight. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday A cold front will sweep through the Bay Area bringing moderate to heavy rain and gusty winds Thursday into Friday. Again, flooding will be possible along with downed trees and isolated power outages. Showers will likely linger into Friday with dry conditions returning region- wide by the upcoming weekend. *A wind advisory is in effect for the North Bay, Santa Cruz Mountains and East Bay Hills late tonight through Thursday. Gusts 50-60 mph possible. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. CAZ508>510-513-516>518-528>530-091400- San Francisco Bay Shoreline-San Francisco Peninsula Coast- East Bay Interior Valleys-Santa Clara Valley Including San Jose- Southern Salinas Valley/Arroyo Seco and Lake San Antonio- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- Northern Salinas Valley/Hollister Valley and Carmel Valley- Northern Monterey Bay-Southern Monterey Bay and Big Sur Coast- 528 AM PST Wed Feb 8 2017 This Hazardous Weather Outlook is for portions of Northern California. .DAY ONE...Today and Tonight Light to occasionally moderate rainfall will continue to impact the region tonight. However, widespread heavy rainfall is not anticipated. Southerly winds will increase tonight. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday A cold front will sweep through the Bay Area bringing moderate to heavy rain and gusty winds Thursday into Friday. Again, flooding will be possible along with downed trees and isolated power outages. Showers will likely linger into Friday with dry conditions returning region- wide by the upcoming weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
In the hours before
Local storm report, Feb 8, 5:03 AM PST, 4 hours 15 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
503 AM PST WED FEB 08 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0425 AM DEBRIS FLOW 8 WNW SANTA CRUZ 37.00N 122.18W
02/08/2017 SANTA CRUZ CA LAW ENFORCEMENT
MUD AND ROCKS ON ROAD. BONNY DOON RD/SR1
&&
MMEHLEThe office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 7, 5:13 PM PST | Areal Flood Warning | MTR | Monterey | 6 hr |
| Feb 7, 5:27 PM PST | Flash Flood Warning | MTR | Alameda | 2 hr |
| Feb 8, 1:57 AM PST | Wind Advisory | MTR | Marin, Napa, San Mateo, Santa Clara, Santa Cruz, Sonoma | 38 hr |
| Feb 8, 2:23 AM PST | Small Craft Advisory | MTR | 43 hr | |
| Feb 8, 8:37 AM PST | Areal Flood Warning | MTR | Sonoma | 4 days |
| Feb 8, 2:43 PM PST | Coastal Flood Warning | MTR | Marin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma | 21 hr |
Nearby
Flash Flood Watches in California, 2017Every flash flood watch in 2017
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.