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QPFERD
Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
503 PM EST Sat Feb 15 2025
Day 1
Valid 2147Z Sat Feb 15 2025 - 12Z Sun Feb 16 2025
...THERE IS A HIGH RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE
LOWER MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS...
2147Z Update...The Moderate Risk was extended farther into
southwest Virginia to account for their flash flood emergencies.
Recent radar/satellite imagery late this afternoon shows a
continued axis of training moderate to heavy rainfall from Arkansas
across southern IL into portions of KY and southwest VA. Inflow at
850 hPa is from the west-southwest at 50+ kts and was quasi-
parallel on the cool/overrunning side a set of warm fronts in an
area of low- to mid-level frontogenesis. Expectation is for the
flow to remain parallel in nature of the above frontal alignment.
Precipitable water values are 1.3-1.5" and flash flood guidance is
quite depressed, approaching zero, within an area of completely
saturated soils. The various Moderate and High Risk areas remain
supported, given the above. The best instability remains across
portions of the Mid- South, where mesocyclone formation and
training convective bands are most likely. A variety of new flash
flood warnings are covering that scenario from central AR into the
Bootheel of MO.
Significant rainfall remains in the offing for a large portion of
the Lower Mississippi and Ohio Valleys. Expect a continued large
expanse of flash flood and areal flood warnings into tonight with
more flash flood emergencies possible. Confidence remains very high
for potential life- threatening flash flooding occurring in the
above areas.
Roth/Kleebauer
Day 2
Valid 12Z Sun Feb 16 2025 - 12Z Mon Feb 17 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL IN PORTIONS OF THE MID-ATLANTIC...
20Z Update: The main change from the previous forecast was a
further expansion of the MRGL risk to the west and southwest across southwestern VA and northwestern NC where trends within the 12z
HREF highlights lingering convective schemes over the terrain in
the first 3-6 hr window of D2, an area that will be well-primed and
likely experiencing ongoing flood concerns from the previous
period. Already some significant flooding within the far southwest
section of VA due to the combination of persistent mod/heavy
rainfall and snow melt. HREF 1"/6-hr probs are between 50-70% with
much of the precip falling in a few hrs within the short term
window 12-18z Sun. Progressive nature of the precip will aid in
maintaining a very low-end prob for flash flooding for other areas
downstream within the Mid-Atlantic, including the metro corridor
from Richmond to Boston. Still maintaining non-zero probs for those
areas across the Megalopolis, but prob fields are not signaling
much in the way of confidence to expand the risk area further
north, so maintained continuity from previous forecast.
Kleebauer
..Previous Discussion..
A Marginal Risk was maintained across portions of the Mid-Atlantic,
mainly as a reflection of the potential for brief, heavy rains
advancing along the cold front moving across the region early in
the period. While these storms are expected to be progressive,
with widespread additional heavy totals not expected, moist soils
further saturated by rain in the previous period may encourage
isolated flash flooding responses, especially across portions of
southwestern to central Virginia.
Pereira
Day 3
Valid 12Z Mon Feb 17 2025 - 12Z Tue Feb 18 2025
The probability of rainfall exceeding flash flood guidance is less
than five percent.
Pereira/Kleebauer
Day 1 threat area:
https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5PQF869oRDjn9fMbLVudzrbFAJOTCfw6qaosg2Bk08_N= cTy08SBwuDQRx0nVN-M_rNsDm9VoQOU7K5bR5jg2mG647fg$=20
Day 2 threat area:
https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5PQF869oRDjn9fMbLVudzrbFAJOTCfw6qaosg2Bk08_N= cTy08SBwuDQRx0nVN-M_rNsDm9VoQOU7K5bR5jg2if8A-cY$=20
Day 3 threat area:
https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5PQF869oRDjn9fMbLVudzrbFAJOTCfw6qaosg2Bk08_N= cTy08SBwuDQRx0nVN-M_rNsDm9VoQOU7K5bR5jg2VKxVk70$=20
=3D =3D =3D
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