Quantitative Precipitation Forecast
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FOUS30 KWBC 260102
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 PM EDT SUN JUN 25 2017

...VALID 01Z MON JUN 26 2017 - 12Z MON JUN 26 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
50 NNE SWW 30 SE HOB 20 W PEQ 35 SSE MMCS 25 WNW MMCS 15 N LRU
40 E TCS 25 NW 4CR 15 NNE 4MY 25 N CQC 35 SE LVS 35 ESE LVS
20 E LVS 20 SE SKX 35 SSE TAD 15 NNW VTP 15 SW PUB 25 WSW SPD
20 N HHF 45 NNE CDS 20 W F05 50 NNE SWW.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
30 N DUX 15 WSW PPA 30 WSW CDS 30 ESE LBB 45 NNE HOB 35 E ATS
20 ENE GDP 25 E ELP 25 ESE LRU 25 NW HMN 4CR 10 NNW CQC
45 SE LVS 45 WNW TCC 35 NNE LVS 10 NNW CAO 30 N DUX.


0100 UTC UPDATE...

UPDATED THE DAY 1 ERO TO REMOVE THE LINGERING MARGINAL RISK AREA
ALONG THE GULF AND SOUTHEAST COASTS...AS THE INSTABILITY AND
CONVECTIVE TRENDS (LARGELY DIURNALLY-DRIVEN) CONTINUE TO DIMINISH.

2130 UTC UPDATE...

MADE A FEW MAINLY COSMETIC CHANGES TO THE DAY 1 ERO...PARTICULARLY
OVER THE SOUTHERN HIGH PLAINS BASED ON THE LATEST MESOANALYSIS AND
CONVECTIVE TRENDS LATE THIS AFTERNOON. STRENGTHENING UPPER
DIVERGENCE WITHIN A DIFLUENT FLOW PATTERN ALOFT...ALONG WITH
INCREASING RIGHT-ENTRANCE REGION FORCING VIA THE CURVED UPPER JET
STREAK OVER THE LOWER MO VALLEY...WILL FUEL MORE WIDESPREAD
CONVECTION INTO THE EVENING HOURS OVER THE SOUTHERN HIGH PLAINS.
FURTHERING THE COVERAGE AND INTENSITY OF THE HEAVIER CORES WILL BE
THE STRONG DEEP LAYER INSTABILITY (MIXED LAYER CAPES 2000-3000
J/KG)...ANOMALOUS DEEP MOISTURE (PWS ~2 STANDARD DEVIATIONS ABOVE
NORMAL)...AND THE STRENGTHENING SOUTH-SOUTHEASTERLY (UPSLOPE)
LOW-LEVEL FLOW. THE DEGREE OF DIRECTIONAL SHEAR (0-6KM BULK SHEAR
AOA 40 KTS)...ALONG WITH THE SUB-CLOUD DRY AIR AND DEEP-LAYER
INSTABILITY...WILL FAVOR A FAIRLY STRONG OUTFLOW COMPONENT AND
INCREASED FORWARD THE PROPAGATION WITH TIME THIS
EVENING...EVIDENCED BY THE MODEL FORECAST NORTHWESTERLY CORFIDI
VECTORS RISING TO 15-20+ KTS. WHILE THIS WILL REDUCE THE POTENTIAL
FOR TRAINING...THE THERMODYNAMIC ENVIRONMENT WILL NONETHELESS
FAVOR ROBUST SHORT TERM RAINFALL RATES...TO THE TUNE OF 1.5-2.0+
INCHES/HOUR UNDERNEATH THE STRONGEST CORES WITHIN THE SLIGHT RISK
REGION PER THE LATEST HIGH RES CAMS.

HURLEY


...SERN US/CENTRAL GULF COAST TO TX/NM...

THE THREAT OF EXCESSIVE RAIN IS POSSIBLE TODAY FROM PARTS OF THE
SOUTHEAST THROUGH THE CENTRAL GULF COAST STATES AND ACROSS TX INTO
NM. A QUASI-STATIONARY FRONTAL ZONE WILL INTERACT WITH CONTINUED
DEEP TROPICAL MOISTURE FOR SCATTERED TO WIDESPREAD
SHOWERS/THUNDERSTORMS WITH SOME ORGANIZATION. LIGHT STEERING FLOW
WITH THIS ACTIVITY WILL KEEP FLOODING CONCERNS IN THE FORECAST, AS
HI-RES SUITE INDICATE SOME VERY LOCALIZED IMPRESSIVE AMOUNTS. ONE
AREA THE HI-RES MODELS PREFER FOR LOCALLY HEAVY RAIN IS ALONG
COASTAL SECTIONS OF SC INTO SOUTH GA AND THE FL PANHANDLE AND WPC
UPGRADED HERE TO A SLIGHT THREAT. MEANWHILE BACK UPSTREAM TO THE
SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS, POSSIBLE ROUNDS OF
ORGANIZED CONVECTIVE HEAVY RAINFALL WILL BE POSSIBLE EARLY TODAY
AND PICK BACK UP LATE THIS AFTERNOON INTO MON MORNING. WEAK UPPER
DISTURBANCES ROUNDING THE SWRN UPPER RIDGE WILL STREAM SOUTH AND
EAST THROUGH NM INTO THE TX PANHANDLE AND WEST TX TO INTERACT WITH
MOIST UPSLOPE COMPONENT FOR POSSIBLE ORGANIZED HEAVY RAINFALL. THE
FIRST AREA OF CONCERN IS FROM NERN NM INTO THE TX PANHANDLE AND AN
ARRAY OF HI-RES MODELS SUGGEST NOT JUST ORGANIZATION BUT POTENTIAL
EXCESSIVE RAINS. THEN THIS AFTN, ANOTHER WEAK DISTURBANCE ALOFT
WILL TAKE A MORE SOUTHERLY TRAJECTORY TO HIGHLIGHT HEAVY RAINFALL
ACROSS SERN/SOUTHERN NM INTO PERHAPS WEST TX. WPC ALSO WENT WITH A
SLIGHT THREAT GIVEN STRONG MODEL CONSENSUS.


MUSHER

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