A broad area of low pressure across the Great Lakes region stalled out well to the west of the region early on Sunday April 30th. A secondary area of low pressure developed and moved up the Eastern Seaboard and tracked across interior New England from Sunday April 30th through Monday May 1st.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GYX wrote it up.
A broad area of low pressure across the Great Lakes region stalled out well to the west of the region early on Sunday April 30th. A secondary area of low pressure developed and moved up the Eastern Seaboard and tracked across interior New England from Sunday April 30th through Monday May 1st. Heavy rainfall occurred, and flooding was enhanced for this weather event due to the seasonal timing of the rains with spring soils being high in moisture and the vegetation still dormant. These two factors lead to increased run-off. Rain started across southern and coastal areas early on Sunday April 30th, with the heaviest rainfall Sunday night into early Monday morning. The rainfall on Sunday produced limited flooding, but set the stage for what was to come by swelling rivers and filling ditches ahead of the heavier rain. Heavy rain started around 3 AM and continued through 10 AM Monday with rainfall rates between 1 to 1.5 inches an hour. This caused flooding to rapidly develop, resulting in widespread flash flooding. The rainfall ended by midday on Monday May 1st. Runoff spilled into tributary rivers and major rivers that led to ongoing flooding for the next several days with most rivers cresting late on Monday May 1st or on May 2nd.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Gray, ME wrote its last area forecast discussion before the first event at May 1, 2:47 AM EST, 2 hours 57 minutes earlier.
Area Forecast Discussion
National Weather Service Gray ME
347 AM EDT Mon May 1 2023
.SYNOPSIS...
Heavy rain will end this morning. However, river flooding may
last a few days due to runoff. Unsettled conditions linger
behind this system through the middle of this week as an upper
low remains near the area. Improvement in weather and
temperatures is foreseen this weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Low pressure just to the south and west of our CWA early this
morning will lift northward, bringing a cold front across the
region through midday or so. However, back edge of the steady
heavy rain is already clearing out of southern NH and will
quickly pull northward this morning, eventually coming to an end
in the north by late morning. The afternoon will be mostly dry
with temperatures rising into the 60s for many locations. With
instability still present under the upper low, widely scattered
showers and perhaps a few thunderstorms will be possible this
afternoon, mainly across NH.
In the meantime, in the heavy rain area, flash flooding remains
possible. In addition, on the coastal plain and just inland,
strong easterly winds will gust to around 40 knots, which
necessitated the expansion of the wind advisory. The bulk of the
strong winds should be east of the area by 12z. Winds are
especially strong in convective elements, at times leading to
brief periods of very low visibility. Thunder remains possible
in the heaviest rainband as it continues to move northward.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Tonight should be dry, at least in the beginning but another
spoke of vorticity rounding the parent trough will bring another
round of showers to southern and western NH between 08z and 12z.
These will rotate northeastward early Tuesday morning affecting
the forecast area with widespread showers once again for the
bulk of the day. A few thunderstorms will be possible as well.
Highs will be a good 5 to even 10 degrees colder than today's
expected values.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Overview: Broad upper low pressure system will keep the region
rainy/showery Wed into Thursday. Conditions are set to slowly
dry out through the weekend as high pressure moves across
northern New England. Other weak disturbances may bring rounds
of showers into early next week. Overall, temperatures will
exhibit a warming trend into the weekend, with refreshing temps
in the 60s or around 70 possible Sat/Sun.
Details: The same broad cyclonic rotation that has provided the
rainy conditions through the weekend will continue to funnel
rainy conditions into mid-week. Ensemble guidance is in good
agreement to bring the upper low through the eastern Great Lakes
region and New York state through Tuesday night and Wednesday.
This positions the CWA in an onshore flow scenario, which will
continue cool, damp conditions through Wednesday and perhaps
much of Thursday.
Current focus of modeled and forecast QPF is in the mountains
and foothills. This is likely where more continuous rainfall is
expected due to added topo lift. Elsewhere, coverage of rain may
be more dependent on instability from daytime warming and the
cooler airmass aloft. Despite the saturated low-level
environment, mid and upper levels are drier when compared to
current impacting system. IVT vectors echo this, with bulk of
advection sheared out to sea. Took NBM QPF and blended some
GFS/ECMWF/NAM in to grab some of the higher guidance where some
of these showers may train. Locations of this will need to be
refined amid higher short range guidance. Worth to monitor given
the very damp start to the week and rising river concerns.
Northerly flow really starts picking up Friday as the low
finally departs over the Mid-Atlantic. This will set up vast
improvement in conditions with the bulk of the weekend looking
dry. This will also allow for temps to bounce back into the 60s
on Saturday, and push towards 70 Sunday.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Short Term...IFR conditions with LLWS and gusty easterly SFC
winds will improve this morning as a dry slot and cold front
moves across the area. A return to VFR is likely for most
terminals this afternoon with gusty southwesterly winds.
Conditions will begin to lower again late tonight to MVFR, with
pockets of IFR in rain expected during the bulk of the day
Tuesday.
Long Term...IFR ceilings likely continue into Wed and overnight.
Improvement to MVFR is possible Thursday, but will likely be
accompanied by continuing SHRA. Further improvement to VFR is
likely Friday into the weekend.
&&
.MARINE...
Short Term...A strong low will track from N-S across New England
this morning with strong east-southeast winds of storm force
early on. Winds ease and shift to a southwesterly direction
this morning with rapidly diminishing winds. SCA conditions and
seas of 10-15ft continue this afternoon. Seas gradually diminish
through Tuesday. Another round of SCA winds will be possible
Tuesday.
Long Term...Occasional SCA conditions due to 25 kt wind gusts
are possible Wed, but more persistent NE gusts expected Wed
night into Thurs AM. Despite winds slackening Thursday, wave
heights remain around 5 ft, particularly on the outer coastal
waters into Friday.
&&
.HYDROLOGY...
Additional flood warnings have been issued...for rivers and
general overland flood warnings. The bulk of the additional
rainfall will fall in the next several hours...so not only is
river flooding possible but flash flooding as well. Low lying
and urban flooding is near certain in the flood watch area
through this morning. Expect more river flood warnings to be
issued with time.
&&
.TIDES/COASTAL FLOODING...
Some minor splashover and beach erosion will be possible around
the time of the morning high tide today.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Flood Watch through Tuesday evening for MEZ012>014-018>028-033.
Wind Advisory until 8 AM EDT this morning for MEZ018>028.
NH...Flood Watch through Tuesday evening for NHZ002>006-008>010-012-
013-015.
Wind Advisory until 8 AM EDT this morning for NHZ014.
MARINE...Storm Warning until 6 AM EDT early this morning for ANZ150>154.
&&
NEAR TERM...Ekster
SHORT TERM...Ekster
LONG TERM...CornwellHazardous Weather Outlook National Weather Service Gray ME 315 AM EDT Mon May 1 2023 MEZ012>014-033-NHZ002>006-008>010-012-013-015-020715- Southern Oxford-Southern Franklin-Southern Somerset- Interior Cumberland Highlands-Southern Coos-Northern Grafton- Northern Carroll-Southern Grafton-Southern Carroll-Merrimack-Belknap- Strafford-Eastern Hillsborough-Interior Rockingham- Western And Central Hillsborough- 315 AM EDT Mon May 1 2023 ...FLOOD WATCH IN EFFECT THROUGH TUESDAY EVENING... This Hazardous Weather Outlook is for south central Maine, western Maine, New Hampshire, central New Hampshire, northern New Hampshire and southern New Hampshire. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Flood Watch. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Flood Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. NHZ014-020715- Coastal Rockingham- 315 AM EDT Mon May 1 2023 ...WIND ADVISORY IN EFFECT UNTIL 8 AM EDT THIS MORNING... This Hazardous Weather Outlook is for southern New Hampshire. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Wind Advisory. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. MEZ007>009-NHZ001-007-011-020715- Northern Oxford-Northern Franklin-Central Somerset-Northern Coos- Sullivan-Cheshire- 315 AM EDT Mon May 1 2023 This Hazardous Weather Outlook is for west central Maine, western Maine, central New Hampshire, northern New Hampshire and southern New Hampshire. .DAY ONE...Today and tonight. Low pressure tracking northward along the East Coast today is expected to bring widespread moderate to locally heavy rainfall to the region. Minor flooding is possible, including minor river flooding early this week. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MEZ018>028-020715- Interior York-Central Interior Cumberland-Androscoggin-Kennebec- Interior Waldo-Coastal York-Coastal Cumberland-Sagadahoc-Lincoln- Knox-Coastal Waldo- 315 AM EDT Mon May 1 2023 ...WIND ADVISORY IN EFFECT UNTIL 8 AM EDT THIS MORNING... ...FLOOD WATCH IN EFFECT THROUGH TUESDAY EVENING... This Hazardous Weather Outlook is for Maine, south central Maine and southwest Maine. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Wind Advisory. Flood Watch. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Flood Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. ANZ150>154-020715- Coastal Waters from Stonington, ME to Port Clyde, ME out 25 NM- Penobscot Bay- Coastal Waters from Port Clyde, ME to Cape Elizabeth, ME out 25 NM- Casco Bay- Coastal Waters from Cape Elizabeth, ME to Merrimack River, MA out 25 NM- 315 AM EDT Mon May 1 2023 ...STORM WARNING IN EFFECT UNTIL 6 AM EDT EARLY THIS MORNING... This Hazardous Weather Outlook is for Atlantic coastal waters. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Storm Warning. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
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</html>The Portland,ME radar (KGYX), 81 km away, was scanning. The volume nearest the first event began at 10:44 UTC.
3 flash flood, 2 flood. Local standard time, as filed.
Locally heavy rain caused New Hampshire Route 113 to close due to flooding in multiple areas between Tamworth and Madison. Route 153 was closed due to flooding in Eaton.
The Saco River came out of banks on May 1st that caused significant flooding to several camps and campgrounds between Conway and Bartlett. The flooding significantly impacted travel in and out of the area due to closed roads. Flooding started on the upper portion of the West Side Road with minor property inundation. The floodwater moved downstream causing significant damage to area campgrounds in North Conway and backwater on the Ellis River. In North Conway a section of West Side Road flooded, cutting off access to several homes. River Road flooded on the west bank of the Saco River flooding agricultural lands. Floodwaters inundated first floors of properties in Transvale Acres. Moat Brook Road flooded cutting off seasonal camps. Widespread agricultural flooding occurred between Conway and Fryberg. The river levels were at the bridge deck of the Saco River Covered Bridge in Conway. The USGS river gage in Conway crested at a 13.6 feet, exceeding the 9 foot flood stage by 4.6 feet.
Rainfall between 0.5 and 1.25 inches fell over still frozen soils in portions of the White Mountains during the morning of May 1. The excessive runoff resulted in significant and multiple washouts on the Kancamangus Highway in Lincoln, which lies between the steep slopes of mountains peaking over 3,000 feet.
Rainfall between 0.5 and 1.25 inches fell over still frozen soils in portions of the White Mountains during the morning of May 1. The excessive runoff resulted in significant and multiple washouts on the Mount Washington Auto-road in the White Mountains.
Locally heavy rain caused Route 16B flooding at the intersection of Route 16 in Center Ossipee.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New Hampshire in 2023Every state in 2023This day in weather historyWarnings in New Hampshire, May 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1102184, 1102196, 1102883, 1105097, 1102186.