Quantitative Precipitation Forecast
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FOUS30 KWBC 241453
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1052 AM EDT SUN MAY 24 2015

...VALID 15Z SUN MAY 24 2015 - 12Z MON MAY 25 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SW KHQI 20 NW LBX 30 SW PSN 25 WNW CNW 10 W RPH 15 SSE HBR
15 ESE GOK 35 WNW CNU 20 SSW FOE 15 N OMA 15 S MML MKT 10 NW CCY
10 E OTM 20 W UIN 20 WSW SUS 30 SW CIR 10 SSE HKA 15 SW OLV
25 NNW GWO 30 SSE TVR 10 SE KEIR 20 SW KHQI.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 N TOR 20 SSW OGA 35 N GLD 15 SE ITR 15 ESE LIC 30 SSW PUM
25 W HLD 10 ENE WRL 10 WSW DHS 40 N TOR.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 WNW SHV 15 ESE DEQ 40 SW RKR 25 NNW MLC 15 NNE CQB
20 NNW GCM 35 ENE JLN 20 N BPK 20 WNW LZK 25 NE IER 25 SE ACP
20 NW KVNP 20 SSW KVBS 15 SE JAS 10 WNW SHV.


...SOUTHERN TO CENTRAL PLAINS AND LOWER TO MID MS VALLEY...


...HEAVY RAINFALL POTENTIAL SHIFTS SLOWLY EASTWARD ACROSS EASTERN
PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS AND TOWARD THE LOWER
AND MID  MISSISSIPPI VALLEY...

THE PRIMARY MORNING ADJUSTMENT WAS TO TRIM THE WESTERN EDGE OF THE
THREAT AREA WHERE ACTIVITY HAS ENDED IN CENTRAL KS DOWN TO
SOUTHEAST TEXAS.  ONE MORE CIRCULATION DRIFTING EAST TOWARDS
NORTHEAST TEXAS WARRANTS CONTINUING A SLIGHT RISK THERE.

THE WIDESPREAD CONVECTION ORIENTED IN A SSW-NNE FASHION EARLY THIS
MORNING IS ALIGNED PARALLEL TO THE MID-UPPER LEVEL FLOW...HAS
EXHIBITED SLOW EASTWARD PROGRESSION EARLY THIS MORNING.
THE NEXT IN WHAT HAS BEEN A SERIES OF SHORTWAVES ROUNDING THE
TROUGH BASE WILL LIFT NORTHEAST ACROSS THE RED RIVER AND INTO THE
MID MISSISSIPPI VALLEY BY THE END OF THE PERIOD (12 MON).  THE
ROBUST LLJ (40-50 KTS) AND ANOMALOUS PW VALUES OF 1.75 AND 2.00
INCHES (~2.5 STANDARD DEVIATIONS ABOVE NORMAL) SUPPORTS
CLUSTERS/SEGMENTS OF HEAVY DOWNPOURS.  THE BIGGEST DIFFERENCE FROM
YESTERDAY IS THE MORE LOCALIZED COVERAGE OF HEAVY RAINFALL
POTENTIAL IN THE MODEL/HIGH RESOLUTION ENSEMBLES.

THE MODELS CONTINUE TO SHOW SPREAD IN THE EASTWARD
PROGRESSION/FORWARD PROPAGATION OF THE CLUSTERS OF SHOWERS/STORMS.
WPC UTILIZED THE RGEM AND OTHER HIGH-RES GUIDANCE (SUCH AS THE
WRF-ARW) TO NUDGE THE ACTIVITY A BIT MORE TO THE EAST...GIVEN THE
ANTICIPATION OF STRENGTHENING DEEP-LAYER INSTABILITY DOWNSTREAM
WITH MUCAPES CLIMBING BETWEEN 2000-3000+ J/KG INTO PORTIONS LA AND
AR THIS AFTERNOON. THERE ARE A FEW GLOBAL AND HIGH RES MODELS
WHICH INDICATE BANDS OF HEAVY SHOWER/STORMS SPREADING EAST INTO MS
SO A SLIGHT RISK WAS EXPANDED INTO WESTERN MS.

FARTHER NORTH INTO EASTERN KS/NE AND NORTHERN MO/IA...AHEAD OF THE
MESOSCALE CONVECTIVE CIRCULATION TRACKING TO THE NORTHEAST...THE
DEEP-LAYER INSTABILITY WILL NOT BE AS GREAT...SO THE THREAT IS
STILL SLIGHT GIVEN SOME MODEST INSTABILITY (MUCAPES GENERALLY
UNDER 1500 J/KG) ALONG WITH THE ANOMALOUS PW AND 850-700 MB
MOISTURE FLUX...LOCALLY HIGHER AMOUNTS ARE EXPECTED PER THE HIGH
RES GUIDANCE. AS A RESULT...THE SLIGHT RISK FOR EXCESSIVE RAINFALL
WILL CONTINUE ACROSS THESE AREAS.


...CENTRAL TO NORTH CENTRAL HIGH PLAINS...

SCATTERED TO LOCALLY NUMEROUS SHOWER ACTIVITY IS LIKELY AGAIN IN
THIS ABOVE AVERAGE PW AXIS WITH 700-500 MB VERTICAL VELOCITY
MAXIMA ROTATING AROUND THE BROAD CIRCULATION LEADING TO A LOCALLY
HEAVY RAINFALL OVER PORTIONS OF CENTRAL AND SOUTHEAST WY INTO FAR
WESTERN NE AND NORTHEAST CO. THIS COINCIDES WITH A MAX REGION OF
UPPER DIFFLUENCE AS WELL AS SOUTHEAST-EAST LOW-LEVEL UPSLOPE FLOW
AND FAVORABLE MOISTURE TRANSPORT. LOCALIZED HEAVY RAIN ARE
POSSIBLE WHERE CELLS MOVE SLOWLY...AND CONSIDERING THE RECENT
HEAVY RAINS (LOW FFG VALUES OF 1.5" OR LESS IN 6
HOURS)...ADDITIONAL LOCALIZED SHORT-TERM RUNOFF ISSUES ARE
ANTICIPATED.

PETERSEN
$$




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