Quantitative Precipitation Forecast
Issued by NWS

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000
FOUS30 KWBC 191358
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
957 AM EDT FRI SEP 19 2014

...VALID 15Z FRI SEP 19 2014 - 12Z SAT SEP 20 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
50 SW F05 20 ENE ABI PWG 15 ENE UTS 15 NNW BPT 15 SSE KVBS
30 E KRP 10 WSW MMNL 15 WNW MMPG 20 SE 6R6 70 SSE E38 40 SSW MRF
65 SE MMCS 15 E LRU TCS 55 S ABQ 20 NNW CQC 20 NW TCC 30 WNW AMA
35 SSE PPA 20 ESE CDS 50 SW F05.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 S MRF GDP 30 NW ROW 45 ENE 4CR 40 SSW TCC 35 NE CVN PVW
30 N SWW 45 ENE SJT 35 NNW JCT 35 W E29 20 NNW 6R6 50 SE E38
25 S MRF.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 NE EFD 15 NE EFD EFD GLS 20 S LBX PSX 15 SW 3T5 15 NW AUS
30 N 62H 25 W CXO 40 NE EFD.


SOUTHEAST NM AND PORTIONS OF TEXAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A DEEP MOISTURE PLUME ASSOCIATED WITH ODILE -- WITH PRECIPITABLE
WATER VALUES (PWS) OF 1.50-1.75" -- ALONG WITH ANOTHER ANOMALOUS
PW AXIS SETTING SAIL WELL TO THE NORTH AND NORTHEAST OF T.S. POLO
INTO WESTERN TX, WILL CONTINUE TO OVERWASH A STALLED W-E
STATIONARY FRONT ACROSS SOUTH-CENTRAL AND SOUTHEAST TX THROUGH THE
PERIOD. SOUTH TO SOUTHEAST LOW-LEVEL FLOW WILL CONTINUE AHEAD OF
ODILE`S SLOW-MOVING CENTER OF CIRCULATION, THOUGH IT SHOULD WEAKEN
DURING THE DAY TODAY.  THE MCV/OLD 700 HPA CENTER OF ODILE
SHIFTING EASTWARD INTO NORTHERN TX BY THIS EVENING SHOULD CLEAR NM
OF ADDITIONAL EXCESSIVE RAINFALL POTENTIAL TONIGHT.  WEAK
ANTECEDENT UPPER-LEVEL FORCING WITHIN THE BROAD UPPER RIDGE WILL
GET A BOOST AHEAD OF THE ODILE-RELATED CIRCULATION AND WITH
INCREASED UPPER LEVEL DIFFLUENCE.  WHILE LOW-LEVEL INFLOW IS
EXPECTED TO WEAKEN TODAY, SATURATED SOILS BEDEVIL THE REGION AND
CANNOT STAND ANY ADDITIONAL RAINFALL FROM ANY SORT OF
THUNDERSTORM, REGARDLESS OF ITS CONVECTIVE MODE.  THUNDERSTORMS
WHICH FORM WITHIN THE REGION COULD ORGANIZE AS 0-6 KM BULK SHEAR
IS NEAR 25 KTS.  MAINTAINED THE MODERATE RISK ACROSS SOUTHEAST NM
AND WESTERN TX TO ACCOUNT FOR THE LOW FLASH FLOOD GUIDANCE VALUES
AND POTENTIAL CONVECTIVE ORGANIZATION WITHIN THE AREA TODAY. PER
THE MOST RECENT MESOSCALE QPF GUIDANCE... LOCALIZED AMOUNTS OF 6-9
INCHES ARE POSSIBLE AS THE OVERALL MOISTURE-RICH ENVIRONMENT (WARM
RAIN PROCESSES) WILL CONTINUE TO SUPPORT RAINFALL RATES UP TO 2.5
INCHES PER HOUR.

ACROSS SOUTH-CENTRAL AND SOUTHEAST TX, A SEA OF ANOMALOUSLY HIGH
MOISTURE, IN THE 2-2.5" RANGE, NEAR TO ABOVE THE 90TH PERCENTILE
FOR MID-SEPTEMBER, LIES CLOSER TO THE SURFACE BOUNDARY OVER AN
INCREASINGLY SATURATED AREA.  ACROSS SOUTH-CENTRAL TX, CONVECTIVE
ORGANIZATION IS POSSIBLE CONSIDERING 25 KTS OF 0-6 KM BULK SHEAR
ADVERTISED BY RECENT RAP GUIDANCE.  INSTABILITY CAUSED BY DAYTIME
HEATING IN LEAGUE WITH THE AVAILABLE MOISTURE SUPPLY SHOULD
GUARANTEE THUNDERSTORM ACTIVITY WITH HEAVY RAINFALL THIS AFTERNOON
AND EVENING.  ACTIVITY IN SOUTHEAST TX IS ONGOING AND SHOULD
EXHAUST LOCAL INSTABILITY FOR A TIME WHICH COULD FORCE NEW
THUNDERSTORM DEVELOPMENT SOUTHWEST LATER THIS MORNING AND THIS
AFTERNOON DOWN THE FRONTAL BOUNDARY IN ITS ELUSIVE SEARCH FOR
CAPE-RELATED BOUNTY.  OTHER THUNDERSTORMS ARE POSSIBLE ACROSS
SOUTHEAST TX THIS AFTERNOON IF SUNNY SKIES BREAK OUT LATER TODAY,
SO INTRODUCED A MODERATE RISK OF EXCESSIVE RAINFALL.  THE
MESOSCALE GUIDANCE INDICATED THAT LOCAL AMOUNTS OF 3-6" ARE
POSSIBLE IN THIS REGION.  SEE MPD #0391 FOR MORE ON SHORT TERM
EXPECTATIONS FOR CONVECTIVE ACTIVITY IN SOUTHEAST TX THROUGH 16Z.


SOUTHEAST AZ
~~~~~~~~~~~~
PRECIPITABLE WATER VALUES OF 1.75" COMBINED WITH DAYTIME HEATING
TODAY SHOULD LEAD TO TYPICAL MONSOON-LIKE THUNDERSTORM
DEVELOPMENT.  THE 0-6 KM BULK SHEAR (20 KTS OR LESS) AND MAGNITUDE
OF THE 700 HPA INFLOW (10 KTS) IMPLY SINGLE CELL/PULSE CONVECTION
TODAY OVER ANYTHING ORGANIZED.  CONSIDERING RECENT RAINS FROM
ODILE SATURATING THE AREA, FELT IT WAS PRUDENT TO ADD A "SEE TEXT"
HIGHLIGHT TO THIS AREA.  HOURLY RAIN RATES UP TO 2" ARE POSSIBLE
WHERE CELLS MERGE, WHICH COULD LEAD TO A FEW POCKETS OF FLASH
FLOODING THIS AFTERNOON AND EVENING.


ROTH/HURLEY
$$




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