Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 180041
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
840 PM EDT TUE MAY 17 2016

...VALID 01Z WED MAY 18 2016 - 12Z WED MAY 18 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 NW 6R9 25 SE HYI CRP MMRX 60 ENE MMMY 25 WNW MMNL 10 SW MMPG
20 ESE 6R6 55 WSW SJT 15 ENE SJT 25 NW 6R9.



...WEST AND SOUTH CENTRAL TEXAS...

0100 UTC UPDATE...

HAVE SHIFTED THE PREVIOUS SLIGHT RISK AREA A BIT FARTHER SOUTH
ACROSS CENTRAL AND SOUTH TEXAS...BASED ON THE LATEST SPC
MESOANALYSIS/TRENDS (CAPE AND LOW LEVEL INFLOW) AHEAD OF THE MAIN
SURFACE FRONT. THE MAJORITY OF THE OPERATIONAL HIGH-RES
CAMS...INCLUDING RECENT HRRR AND EXPERIMENTAL HRRR RUNS...CONTINUE
TO SHOW THE POTENTIAL OF 3-5+ INCHES WITHIN 2-3 HOURS UNDER THE
STRONGEST CORES.

PREVIOUS DISCUSSION...

A SURFACE COLD FRONT ALONG THE RED RIVER AND EXTENDING BACK INTO
WEST TX WILL SINK SOUTH AND EAST OVER THE NEXT DAY... ALONG WITH A
SURFACE DRYLINE CREEPING EAST FROM SW TO S TX. THESE BOUNDARIES
AND POSSIBLE 850 MB CIRCULATION WILL INTERACT WITH DEEP MOIST ERLY
INFLOW FROM THE GULF OF MEXICO TO RESULT IN THE POTENTIAL OF HEAVY
RAINFALL. BNDRY LAYER MOISTURE CONVERGENCE INVOF THE FRONT AND AN
INCREASE IN INSTABILITY SHOULD TRIGGER SHOWERS/STORMS FROM WEST OF
THE DFW AREA SOUTH TO RIO GRANDE... BETWEEN DRT AND LRD. THE
GLOBAL MODELS AND HI-RES SUITE GENERALLY DEPICT THIS AND WITH FFG
VALUES RELATIVELY LOW... WPC WILL KEEP THE SLIGHT RISK OF
EXCESSIVE RAINS INTACT.


...FL PENINSULA...

A POCKET OF ROBUST UPPER LEVEL DIVERGENCE HAS DEVELOPED THIS
AFTERNOON ACROSS MUCH OF THE FL PENINSULA...IN PARTICULAR THE
CENTRAL 2/3RDS. THE FAVORABLE SYNOPTIC SCALE SUPPORT IS THE RESULT
OF THE SUPPRESSED NORTHERN STREAM WITH A BROAD JET STREAK DROPPING
INTO THE MID ATLANTIC REGION. MEANWHILE...THE UPPER LEVEL
DIFFLUENCE OVER THE FL PENINSULA HAS INCREASED AHEAD OF THE MCV
PUSHING ACROSS THE EASTERN GULF...WHICH ALONG WITH THE FAVORABLE
FORCING SOUTH OF THE NORTHERN STREAM JET AXIS...ALONG WITH THE
CONTRIBUTION FROM THE EAST COAST SEA BREEZE COMPONENT...HAS LED TO
THE DEVELOPMENT OF OF NUMEROUS CONVECTIVE CLUSTERS ACROSS THE
PENINSULA AHEAD OF THE MCS. THE FAVORABLE DYNAMICS WILL COMBINE
WITH A THERMODYNAMICALLY RICH ENVIRONMENT TO PRODUCE LOCALIZE
HEAVY TO POTENTIALLY EXCESSIVE RAINFALL AMOUNTS. MIXED-LAYER CAPES
AROUND 2000-2500 J/KG ALONG WITH THE ANOMALOUSLY HIGH PWS (2-2.25"
PER GPS VALUES) WILL MAKE FOR HOURLY RAINFALL RATES BETWEEN 2-3"
WITHIN THE STRONGEST CELLS...WITH ISOLATED TOTAL RAINFALL BETWEEN
4-7+ INCHES PER THE MAJORITY OF THE 12Z HIGH-RES CAMS AND MOST
RECENT HRRR AND EXPERIMENTAL HRRR RUNS.

MUSHER/HURLEY



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