Quantitative Precipitation Forecast
Issued by NWS

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FOUS30 KWBC 011412
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
912 AM EST SUN MAR 01 2015

...VALID 15Z SUN MAR 01 2015 - 12Z MON MAR 02 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
25 SE PRC 35 SSW PRC 45 WNW LUF 55 NW GBN 35 E YUM 20 SSW NYL
15 WSW NYL 20 SSE BLH 40 NE BLH 30 SE EED 30 S IGM 35 E IGM
45 WSW 40G 30 SSW 40G 25 WSW FLG 25 S FLG 40 ESE PRC 25 SE PRC.


1400 UTC UPDATE

SOUTHWEST ARIZONA

CHANGES TO THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL OUTLOOK WERE
TO EXTEND THE SLIGHT RISK AREA FARTHER TO THE SOUTH ACROSS
SOUTHWEST AZ.  THIS IS TO ACCOUNT FOR THE HEAVY QPF AXES OF THE HI
RES MODELS---ARW---CMC GEM---NMMB.  PW VALUES EXPECTED TO RISE TO
2-3 STANDARD DEVIATIONS ABOVE THE MEAN BY LATE SUNDAY AFTERNOON TO
THE EAST OF THE SOUTHERN CALIFORNIA CLOSED LOW IN AN AREA OF
STRENGTHENING SOUTH SOUTHWESTERLY LOW LEVEL FLOW.  THE COMBINATION
OF THE ANOMALOUS PW VALUES IN A FAVORABLE RIGHT ENTRANCE REGION OF
THE UPPER JET AND ENHANCED UPSLOPE INTO THE TERRAIN WILL SUPPORT
POTENTIAL FOR 1-2 INCHES IN THIS AREA--WITH ISOLATED HEAVIER
TOTALS OF UP TO 4" IN THE FAVORED UPSLOPE REGIONS.

ORAVEC

PREVIOUS DISCUSSION

WRN AZ...

HAVE INTRODUCED A SLIGHT RISK OF EXCESSIVE RAIN FOR AREAS ACRS
CENTRAL AZ FOR THE POTENTIAL FOR LONGER DURATION RAINS TO SHOULD
BECOME INCREASINGLY HEAVIER LATER SUN AND SUN NIGHT. THE
DEVELOPING CLOSED LOW OVER THE SOUTHERN GREAT BASIN WILL SINK ONLY
SLOWLY SOUTH SOUTHWESTWARD INTO CENTRAL TO SOUTHERN CALIFORNIA DAY
1.  AN AXIS OF ABOVE AVERAGE PW VALUES WILL PERSIST DAY 1 ON THE
SOUTHEAST SIDE OF THIS CLOSED LOW FROM THE NORTHERN BAJA/FAR
SOUTHERN CALIFORNIA---INTO THE SOUTHWEST---SOUTHERN GREAT BASIN
INTO THE SOUTHERN ROCKIES.  STG 85H-7H SWLY FLOW TO THE EAST SIDE
OF THE UPR LOW ALONG WITH STRENGTHENING JET DYNAMICS TO THE EAST
OF THE UPR LOW WILL LEAD TO THE POTENTIAL FOR MODERATE TO HEAVY
PRECIP TOTALS IN THE FAVORED AREAS NEAR THE WRN MOGOLLON RIM AREA
AND POINTS SOUTH WITH AREAL AVG AMOUNTS EXPECTED TO BE BETWEEN 1
TO 2 INCHES WITH ISOLD HEAVIER AMOUNTS IN EXCESS OF 4 INCHES IN
THE MORE FAVORED UPSLOPE AREAS.  THE HEAVY RAIN OVER THE STEEPER
TERRAIN WILL LIKELY LEAD TO SOME RAPID RUNOFF ISSUES ACRS THE
OUTLOOK AREA.

SULLIVAN

$$





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