Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FOUS30 KWBC 231522
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1021 AM EST Fri Feb 23 2018

VALID 15Z Fri Feb 23 2018 - 12Z Sat Feb 24 2018


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 ENE 4A9 15 ENE NMM 20 WSW PIB 25 SSE HEZ 35 SSW MLU
30 SE GGG 15 ENE 4F4 10 WSW LNC 15 SSE BWD 20 SW RPH 15 ESE FDR
10 W OKC 20 E SWO 55 SSW SZL 15 ENE TAZ 25 ESE FWA 25 SSW CWAJ
25 NW DSV 20 SSW SYR 40 ENE BGM 25 N MSV 15 WSW MSV ABE
10 NNE LNS 20 NE FDK 20 SSE CBE 20 W W99 30 SE 48I 25 W I16
15 NNW LNP 15 SSW 1A6 25 SW OQT 25 NNE CHA 20 SSW CHA 10 ENE 4A9.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 WSW 1F9 30 ESE SPS 25 NW 1F0 10 WSW ADH 15 SE OKM 15 NNW SLG
30 SE JLN 10 E SGF 40 ESE TBN 20 W FAM 15 SSE MVN 15 ESE BMG
10 W WMO 4I3 10 NE BVI 10 WSW DUJ 15 SSW FIG 15 SSE JST
15 SSE 2G4 25 E 3I2 15 N HTS 20 N SME 40 WSW BNA 20 NW TUP
30 NNE GWO 30 ENE ELD SLR F18 20 WSW 1F9.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 SE HRO 25 ENE BPK 25 SE UNO 20 N M19 LRF 10 NE HOT 20 E DEQ
20 NNE LBR 35 N LBR 30 ESE MLC 15 WNW RKR 25 NE FSM 15 SE HRO.


15z Update:

Convection is expanding in coverage near the Red River across
north central TX into southern OK. This is ahead of a shortwave
evident on the GOES airmass RGB and on the nose of increasing 850
mb moisture transport. This activity will continue tracking
northeast with time, with some continued backbuilding. Looking at
roughly 1-3" of rain with this activity along an axis from north
central TX into eastern OK, northwest AR and southern MO. While
wet, these areas have not seen as heavy of rain as locations
further southeast in AR. Thus grounds may not be quite as
saturated over these areas...and FFG is indeed higher here. Thus
in general current indications are that there may not be a ton of
overlap between the heaviest rainfall today and the axis of
highest amounts over the past few days. Thus, while significant
ongoing flooding is occurring, there is some hope that at least
for today additional rainfall may not exacerbate the problem
significantly. For that reason opted to shrink the moderate risk
area for day 1. Kept a moderate risk for portions of southeast OK
and west central AR...as here we will see some overlap of the
locally heavy rates and lowest FFG as the convection moves
northeastward today. Further southeast across AR additional
rainfall today should be lighter...thus a slight risk should
suffice for now. Also expanded the western extent of the slight
risk a tad northwest to account for our expected axis of highest
totals through the day...favoring an axis similar to the new 12z
runs of the ARW and ARW2. Do not think a moderate is needed here
at this point, as soils are not quite as saturated this far
northwest...but will continue to monitor.

The other area to watch is along the Ohio River near IL/IN/KY.
Some signal that enhanced moisture transport ahead of the wave
lifting northeast over the plains will result tin renewed locally
heavy convective activity later tonight. These areas are
saturated...and should this occur a flash flood risk would likely
develop. Thus will continue to monitor...and may need to consider
a moderate risk here on later updates depending on trends.

Chenard



...Previous Discussion...


Northeast TX/southeast OK---Arkansas---southeast MO---western TN
into the OH Valley

A very broad slight and moderate risk areas were maintained for
the upcoming day 1 period for yet another round of widespread
heavy to excessive rainfall amounts from northeast TX/southeast
OK---across much of Arkansas---southern MO and into the OH valley.
 The current training precipitation from SW to northeastern AR
into western TN may continue into the beginning of the upcoming
day 1 period.  However---the model consensus is then for
precipitation to begin to focus farther to the
northwest---initially from north central TX into southeast OK as
the low level southerly flow re-focuses across this area Friday
morning ahead of northeastward moving height falls embedded in the
southwest flow across the southern plains.  This developing
activity expected to then shift downstream into central to
northern AR---southern MO and into the OH valley. An overall very
favorable pattern will continue for widespread heavy to excessive
precip totals with an axis of much above average pw values---2 to
3+ standard deviations above the mean along and north of the
surface frontal boundary slowly moving northward day 1 across
these areas.  There are some typical model differences with the
latitude of the heaviest precip totals---with WPC leaning toward
the farther south solutions of the hi res arw--nssl wrf---HREF
mean.  This will support the heaviest rainfall and excessive
rainfall potential from northeast TX/southeast OK---central to
northern AR into the OH/MS river confluence area.  No significant
changes were made to the previous outlook for this period.

Oravec

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.