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 161354
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
953 AM EDT TUE SEP 16 2014

...VALID 15Z TUE SEP 16 2014 - 12Z WED SEP 17 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SE HXD 15 ESE SSI SGJ 25 S VQQ 40 ESE VLD 15 W AYS 25 S VDI
20 N SAV 10 W NBC 20 SE HXD.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 NW ROW 15 W CNM 45 SSE GDP 10 SSW GDP 30 WSW GDP 70 SSW GDP
35 SSE MMCS 50 S DMN 70 S DMN 75 ESE DUG 50 WSW OLS 80 SE YUM
30 SW NYL 40 NW BLH 35 S HND 25 ESE LSV 50 NNE IGM 45 SSE SGU
55 NW GCN 20 WNW GCN 45 NNW GCN 45 WSW PGA 25 ENE 40G 35 NNW SOW
20 N SOW 35 E SJN 10 SSE GNT 30 NNE TCS 50 NE TCS 40 SSE ABQ
30 NW 4CR 15 NW ROW.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
65 NNW SVC 70 SE SJN 20 W TCS 30 NNW HMN 20 WSW SRR 35 SE ALM
20 S ALM 15 WNW LRU 20 WSW SVC 25 NW SVC 65 NNW SVC.



SOUTHWEST
~~~~~~~~~
AN INCREASING HEAVY RAIN/POSSIBLE FLASH FLOOD THREAT IS EXPECTED
THIS PERIOD AS MUCH ABOVE AVERAGE PRECIPITABLE WATER VALUES (PWS)
WILL CONTINUE TO PUSH NORTHWESTWARD INTO THE DESERT SOUTHWEST
WITHIN THE NORTHERN PERIPHERY OF ODILE. PW ANOMALIES OF 2-4.5
SIGMAS ABOVE THE MEAN -- NEAR RECORD VALUES FOR MID-SEPTEMBER --
ARE ANTICIPATED ACROSS THE SOUTHWESTERN U.S. FROM FAR SOUTHEAST
CA, FAR SOUTHERN NV, MUCH OF AZ, SOUTHERN NM, AND WESTERNMOST TX.
THERE ARE HINTS WITHIN THE 00Z AND 06Z SSEO NEIGHBORHOOD
PROBABILITIES (USING THE 30%+ CHANCE OF EXCEEDING FLASH FLOOD
GUIDANCE AS A GUIDE) THAT THE EXCESSIVE RAINFALL THREAT SHOULD
ENCOMPASS MUCH OF THE AREA OF SIGNIFICANTLY ABOVE NORMAL MOISTURE,
WHERE 25+ KTS OF 700 HPA INFLOW (PER RECENT RAP RUNS) COULD
ORGANIZE CONVECTION NEAR THE INTERNATIONAL BORDER.  THE EXPECTED
EASTERLY LOW-LEVEL FLOW SHOULD ALLOW ANY CONVECTION WHICH BUILDS
WITHIN TOPOGRAPHY ACROSS SOUTHEAST AZ AND THE MOGOLLON RIM TO
MIGRATE OUTWARD TOWARDS VALLEY/DESERT FLOORS TODAY.

THE BIG QUESTION REMAINS WHERE INSTABILITY WILL MAXIMIZE TODAY.
MORNING SATELLITE TRENDS SUGGEST PLACES JUST OUTSIDE ODILE`S
OUTFLOW JET/CLOUD SHIELD NEAR THE LOWER COLORADO RIVER VALLEY AND
THE MOGOLLON RIM COULD BE THE MOST UNSTABLE, AND THAT RAINFALL
ACROSS SOUTHEAST AZ AND SOUTHERN NM COULD BE MORE STRATIFORM OR
MORE OF A LONGER DURATION FLOOD CONCERN RATHER THAN A FLASH FLOOD
CONCERN THROUGH TONIGHT.  AFTER THE MORNING BRIEFING FROM
SAB/NESDIS AND COORDINATION WITH OUR METWATCH DESK, THE SLIGHT AND
MODERATE RISKS FOR EXCESSIVE RAINFALL WERE RESTRICTED FROM THE 12Z
ISSUANCE TO NEAR AND EAST OF THE LOWER COLORADO RIVER VALLEY AND
TO SOUTHERN NM RESPECTIVELY.  LOCAL AMOUNTS OF 2-4" ARE POSSIBLE
HERE WHERE CELLS MERGE AND/OR TRAIN, WHICH WOULD APPROACH ANNUAL
AVERAGE RAINFALL AMOUNTS FOR THE REGION.  THE EXCESSIVE RAINFALL
EVENT EXPECTED OVER THE NEXT FEW DAYS COULD RIVAL THAT OF MONDAY
SEPTEMBER 8 WHICH OCCURRED AROUND THE PERIPHERY OF NORBERT.


COASTAL SOUTHEAST AND FAR NORTHEAST FLORIDA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A SLIGHT RISK AREA LIES ALONG COASTAL GA AND FAR NORTHEAST FL THIS
PERIOD FOR ANOTHER ROUND OF POTENTIALLY HEAVY TO ISOLATED
EXCESSIVE RAINFALL AMOUNTS.  AN AXIS OF ABOVE AVERAGE PW VALUES --
1.5+ STANDARD DEVIATIONS ABOVE THE MEAN -- WILL PERSIST THIS
PERIOD IN THE VICINITY OF THE WEAKENING STATIONARY FRONTAL
BOUNDARY CURRENTLY STRETCHING ALONG THE GULF COAST INTO THE
COASTAL SOUTHEAST.  WIDESPREAD SCATTERED CONVECTION LIKELY AGAIN
ALONG AND SOUTH OF THIS FRONT IN A REGION OF ENHANCED UVVS FROM
FAVORABLE RIGHT ENTRANCE REGION UPPER JET DYNAMICS EXPECTED TO
MOVE ACROSS THIS AREA LATE AFTERNOON/EVENING.  ISOLATED VERY HEAVY
RAINFALL AMOUNTS HAVE FALLEN THE PAST TWO DAYS ALONG COASTAL
SECTIONS OF SC AND GA---WITH THIS POTENTIAL AGAIN POSSIBLE ALONG
COASTAL GA INTO FAR NORTHEAST FL.  THE HIGH RESOLUTION RUNS ARE
MOST EMPHATIC ABOUT HEAVY RAINFALL POTENTIAL ACROSS THESE
AREAS---WITH ISOLATED TOTALS OF 3-5"+ POSSIBLE.  ALTHOUGH NOT
INCLUDED IN THE GRAPHIC, HEAVY RAIN CONCERNS ALSO SPREAD UP THE SC
COAST AND ACROSS THE CAROLINA PIEDMONT.

ROTH/ORAVEC
$$




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