Flood in Oregon, April 8 to 9, 2019

Area Forecast Discussion
National Weather Service Medford OR
956 AM PDT Mon Apr 8 2019

.DISCUSSION...An atmospheric river (AR) is still pounding the
area west of the Cascades with waves of moderate to heavy rainfall
this morning. Storm total rainfall reports so far have been
extremely impressive for April in many areas, and especially in
Curry County. A Mesowest summary for there shows widespread
amounts of 6-12 inches, with the highest amounts in the Coast
Ranges. With several more hours to go, this will likely go down as
a(n) historic 2-day April rainfall. There are a wide range of
flood products out across the area, so please refer to the point
and click map on our home page for more information...or also the
"Rivers and Lakes" section for specific river/lake/drainage
information. The rain will continue, heavy at times, through this
afternoon, so be on the lookout for additional flood
advisory/warning products. We're getting heavier rain now in the
Rogue Valley and this has brought the airport total up over 1.00
inch for the event so far. Still expecting another 0.50-1.00 inch
of rain through tonight.

An upper trough offshore will gradually give the main band of the
AR a kick south and eastward this evening pushing east of the
Cascades and then across SE portions of the forecast area
overnight. While the heavy rainfall associated with the AR will
end west of the Cascades tonight, there can still be potent
showers associated with the upper trough and also the potential
for lightning. Periods of moderate to heavy rain will move
through portions of northern California and the East Side, where,
thus far, rainfall has been comparatively light. Streams and
creeks and perhaps even some rivers there may swell to bankfull on
Tuesday. The upper trough will push inland Tuesday night and it
should showers will finally end. Wednesday we should get a
reprieve with a dry day and rivers, streams and creeks gradually
subsiding. -Spilde

&&

.AVIATION...For the 08/12 TAFS...Moderate to heavy rain will
produce a mix of MVFR and IFR through today at west side locations.
A period of particularly intense rain is expected as a front moves
through this afternoon, and then rain changes to showers. Showers
may be heavy and there is also a slight chance of thunderstorms into
the evening. On the east side, showers will gradually become
widespread rain with conditions lowering to IFR as the front
approaches. There will also be a slight chance of thunderstorms this
afternoon and evening on the east side. -Wright

&&

.MARINE...Updated 900 AM PDT Monday, 8 April 2019...No change to the
forecast this morning. Previous discussion follows. Seas will remain
steep into Tuesday, improving first over the inner waters.
Low pressure will gradually push inland today and winds will shift
from southwest to northwest this evening. North winds will then
increase tonight into early Tuesday as high pressure approaches from
the west. A more typical northerly flow will develop later Tuesday
and persist into Thursday, and winds and seas should remain below
Small Craft Advisory criteria. There is a chance that northerly wind
waves become steep south of Cape Blanco late Thursday into Friday.
DW/Keene/MTS

&&

.PREV DISCUSSION... /Issued 455 AM PDT Mon Apr 8 2019/

AVIATION...For the 08/12 TAFS...Moderate to heavy rain will
produce a mix of MVFR and IFR through today at west side locations.
A period of particularly intense rain is expected as a front moves
through this afternoon, and then rain changes to showers. Showers
may be heavy and there is also a slight chance of thunderstorms into
the evening. On the east side, showers will gradually become
widespread rain with conditions lowering to IFR as the front
approaches. There will also be a slight chance of thunderstorms this
afternoon and evening on the east side. -Wright

MARINE...Updated 345 AM PDT Monday, 8 April 2019...Seas will
remain steep into Tuesday, improving first over the inner waters.
Low pressure will gradually push inland today and winds will shift
from southwest to northwest this evening. North winds will then
increase tonight into early Tuesday as high pressure approaches from
the west. A more typical northerly flow will develop later Tuesday
and persist into Thursday, and winds and seas should remain below
Small Craft Advisory criteria. There is a chance that northerly wind
waves become steep south of Cape Blanco late Thursday into Friday.
DW/Keene

PREV DISCUSSION... /Issued 245 AM PDT Mon Apr 8 2019/

SHORT TERM...An Atmospheric River (AR) remains aimed at us this
morning and continues to produce heavy rain from the south coast
and inland roughly along the Umpqua Divide. Rainfall amounts
along the coast, adjacent coast ranges, and even into the Umpqua
Basin have been very impressive over the last 24 hours and, as
predicted, some of the highest rainfall amounts ever recorded in
April in many locations. Over the last 24 hours, we've seen
roughly 1-2 inches in the Umpqua Basin, 2-4 inches over the Coos
Coast and Cascades north of highway 140, and 3-6 inches (locally
over 8 inches) in Curry County. Included in these numbers are
daily rainfall records in North Bend (3.17") and Roseburg
(1.98"). Incidentally, both of those are also records for April
and the second highest 24 hour rain total in either March or
April on record. The highest rain total, so far, has been 8.3
inches at a station a couple of miles up the Chetco River from
Brookings. Much less rain fell in other areas, but pretty much all
locations from the Cascades west got at least some rain,
including a daily record amount at Medford (0.55").

As far as impacts from this rain: we've received numerous reports
of water over roadways, mud/landslides, and areal flooding,
especially over Coos and Douglas Counties. The main stem rivers
are still doing OK, but smaller, flashy creeks and drainages have
been rising rapidly, and so we upgraded the Flood Watches to
Warnings for all of Coos, Curry, and Douglas Counties.

The most intense rain has moved slightly south and now stretches
from Curry County along the Umpqua Divide and into the Cascades.
The AR will remain over us today, and while it will likely waver
a little north and south at times and fluctuate in intensity
today, it will likely continue to pound roughly this same corridor
much of today. The back edge of the main front is approximately
350 miles offshore and moving toward the coast, but it is going to
be until late this afternoon or evening before it finally pushes
through. We expect a burst of very heavy rain as the front moves
through, and this is when we'll probably see our heaviest rain in
Medford. Even as this front and the band of persistent rain
finally pushes through, then we'll get the convection associated
with the upper trough which could bring moderate to heavy showers
(perhaps even with lightning) to already saturated or possibly
flooded areas. For these reasons, we're going to extend our flood
watches and warnings out through this evening for west side
locations.

While the east side has been left out of the rain for the most
part, guidance does show a soaking rain later today and these
evening as the aforementioned front moves over there. This
combined with snowmelt may also produce localized flooding on the
east side, and we may be extending flood watches farther east later
this morning. Prior to the front and rain arriving, gusty winds
will continue across the east side today. The strongest winds are
already occurring in Lake County, and a wind advisory remains in
effect through early evening. This all finally winds down Tuesday,
and that should be a dry, cool, and breezy day. -Wright

LONG TERM...Extended discussion, Wednesday through next Sunday.
As over the past several days he GFS and ECMWF operational runs are
in fairly good agreement starting Wednesday. They remain in good
agreement with a front moving down the back side of a ridge that is
well offshore Wednesday night. However, as we head into Thursday the
GFS is showing another front sliding down the back of the building
ridge, while the ECMWF continues to bring down a closed low, and a
much wetter system down into the region Thursday. The EC has been
consistent with this for the past several days and will continue with
this solution. The upper low continues to move to the southeast with
an upper ridge building in behind Friday. This ridge shifts eastward
with the GFS and ECMWF coming into agreement again, with an upper
trough moving in and bringing another front into the region
Saturday.

-Sven

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Flood Watch through this evening for ORZ029>031.
     Wind Advisory until 8 PM PDT this evening for ORZ030-031.
     Flood Watch through this evening for ORZ021>025.
     Flood Watch through this evening for ORZ026.

CA...Flood Watch through this evening for CAZ080.
     Flood Watch through this evening for CAZ082-083.
     Flood Watch from 3 PM PDT this afternoon through late tonight
     for CAZ085.

Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT this
     evening for PZZ350-356-370-376.

MAS/TRW/NSK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
757 AM PDT MON APR 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0757 AM     HEAVY RAIN       10 NNW GOLD HILL        42.57N 123.09W
04/08/2019  M3.00 INCH       JACKSON            OR   TRAINED SPOTTER

            24 HRS ENDING 8 AM.

&&

MTS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
811 AM PDT MON APR 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0809 AM     HEAVY RAIN       6 E GOLD BEACH          42.42N 124.31W
04/08/2019  M9.17 INCH       CURRY              OR   TRAINED SPOTTER

            24 HRS ENDING 8 AM.

&&

MTS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
847 AM PDT MON APR 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0846 AM     HEAVY RAIN       5 NNE SELMA             42.35N 123.57W
04/08/2019  M4.31 INCH       JOSEPHINE          OR   TRAINED SPOTTER

            24 HRS ENDING 8:30 AM.

&&

MTS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
848 AM PDT MON APR 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0847 AM     HEAVY RAIN       2 SSE PISTOL RIVER      42.26N 124.39W
04/08/2019  M3.95 INCH       CURRY              OR   TRAINED SPOTTER

            24 HRS ENDING 8 AM.

&&

MTS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
907 AM PDT MON APR 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     HEAVY RAIN       5 E WINCHESTER          43.29N 123.25W
04/07/2019  M0.71 INCH       DOUGLAS            OR   TRAINED SPOTTER

            24 HRS ENDING 8 AM.

&&

MTS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
939 AM PDT MON APR 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0938 AM     HEAVY RAIN       2 ENE MURPHY            42.36N 123.29W
04/08/2019  M2.64 INCH       JOSEPHINE          OR   TRAINED SPOTTER

            24 HRS ENDING 8:30 AM.

&&

MTS