Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 201129
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
629 AM CDT Mon Mar 20 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 330 AM CDT Mon Mar 20 2017

After the elevated storm clusters exit this morning, Canadian high
pressure to dump down the upper midwest and battle central plains
to OH RVR Valley llvl baroclinicity during the midweek. Then
large cyclone still indicated by the latest run medium range
models to lift out acrs the mid CONUS in almost a REX type block
pattern at week`s end.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 330 AM CDT Mon Mar 20 2017

Most of the latest run convective allowing models move the ongoing
elevated storm clusters east of the DVN CWA by 12-13z this morning.
But in case of some back-building on nose of lingering west-
southwest 40-50 KT LLJ, will keep at least low POPs percolating in
the far east through mid morning before normal nocturnal jet
interruption occurs. Then as the adjacent frontal system sags
south and southeast of the local area through late afternoon,
additional convective redevelopment will look to occur along the
boundary in diurnal instability and convergence, but should take
place just east and southeast of the eastern CWA border and will
keep the fcst dry during the midday into the afternoon. Cold air
lag behind the front and some afternoon breaks in the cloud cover
should allow for mild high temps in the upper 50s to 60s acrs the
CWA, but low confidence on how mild to go.

Sfc ridge dumps down the northern plains and upper midwest tonight
for cooler air intrusion, but overrunning areas of mid and high
clouds along ongoing west-northwesterlies aloft may prevent cooler
temps than fcst...much of the area mid and upper 30s.

.LONG TERM...(Tuesday through next Sunday)
ISSUED AT 330 AM CDT Mon Mar 20 2017

Tuesday and Wednesday...will side with the drier and consistent
00z ECMWF for an isentropic lift mainly light cold rain event acrs
the west into south half of the CWA late Tue morning and
afternoon along westerly aligned llvl baroclinicity. Most rainfall
amounts under a tenth of an inch. Then seasonably strong re-
enforcing Canadian high projected to dump down Tue night and
bring about cold scouring effect...lows in the 20s by Wed morning.
Dry but below normal temps for Wed under the brunt of the
anticyclone.

Thursday...latest run medium range models, again with a bias
toward the ECMWF, move the ridge out allowing for return flow
warming regime to commence this day. Wing of WAA-type precip is
projected to sweep north acrs the CWA as the day progresses, and
the model blends suggest the precip to start out as a wintry mix.
But feel a later day/afternoon arrival would allow it to be mainly
rain as opposed to wet snow mix. Then brunt of large scale
convergent WAA precip band to look to set up mainly to the north
of the area acrs MN into WI by Thu night.

Friday through Sunday...Large Rex blocked closed cyclone to roll
out acrs the mid CONUS or Midwest Fri into Sat. Plenty of time
for things to change in the medium range models with timing,
moisture draw and placement, but current progs suggest increasing
showers and some thunderstorms feeding up acrs the area from the
south in organized warm moist conveyor up off the Gulf. Current
system placement suggests the best chance for strong to severe
storms to occur just to the south of the area acrs the low to mid
MS RVR Valley late Fri into Fri night, but the southern fcst area
may also be at risk. Seasonably heavy rainfall may also be a
factor up acrs much of the CWA by Fri evening. Mild highs in the
60s and 70s possible on Fri despite the increasing moisture and
before the widespread precip advects up this way. The system then
projected to slow-roll into the GRT LKS through Sunday making for
a rather damp Sat for the local area.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
ISSUED AT 627 AM CDT Mon Mar 20 2017

VFR conditions with skies becoming fair as winds shift to the
north at 5 to 15 MPH by late morning behind a cold front.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.

&&

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...12
AVIATION...Nichols


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