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FXUS64 KBMX 131206 AAA
AFDBMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BIRMINGHAM AL
706 AM CDT MON APR 13 2015

.UPDATE...
FOR 12Z AVIATION.

&&

.DISCUSSION...

LOOKING AT THE RADAR THIS MORNING...PRECIPITATION IS SLOWLY MOVING
NORTHWARDS ACROSS THE STATE. SO FAR...THUNDERSTORM ACTIVITY HAS
BEEN LIMITED TO ALONG THE IMMEDIATE GULF COAST. CURRENT WATER
VAPOR AND RAP UPPER AIR ANALYSIS INDICATES A CLOSED LOW ACROSS NEW
MEXICO. SOUTHWESTERLY FLOW ALOFT ACROSS THE SOUTHERN PLAINS AND
LOWER MISSISSIPPI RIVER VALLEY CONTINUED TO ADVECT IN DEEP
MOISTURE ACROSS THE AREA. PW VALUES ARE ALREADY OVER 1.5 INCHES
ACROSS THE AREA WHICH IS OVER THE 90TH PERCENTILE FOR MID-APRIL.
DUE TO THE ANOMALOUSLY HIGH PW VALUES AND CONTINUED PUSH OF
PRECIPITATION FURTHER NORTH...WENT AHEAD AND INCREASED POPS TO 100
PERCENT ACROSS THE AREA. FOR TODAY...EXPECT PRECIPITATION WILL
CONTINUE TO SPREAD NORTHWARD ACROSS THE AREA WITH DEEP MOISTURE IN
PLACE. LOCATIONS ALONG THE COAST HAVE ALREADY RECEIVED RAINFALL
AMOUNTS OF OVER 5 INCHES. DO NOT EXPECT TOTALS NEAR THIS HIGH IN
THE FORECAST AREA. EXPECT AMOUNTS FROM 1-2 INCHES WILL BE MORE
REALISTIC ACROSS CENTRAL ALABAMA. ONE-HOUR FLASH FLOOD GUIDANCE
VALUES RANGE FROM ROUGHLY 2-3 INCHES AND EXPECT RATES WILL REMAIN
BELOW THIS THRESHOLD. THERE COULD BE SOME LOCALIZED FLOODING
ISSUES IN AREAS OF POOR DRAINAGE BUT NOTHING WORTHY OF ADDING A
MENTION INTO THE HWO.

THE CHALLENGE BEYOND TODAY WILL BE THE FLOODING POTENTIAL. IT
LOOKS AS THOUGH THERE WILL BE BRIEF REPRIEVES FROM THE WIDESPREAD
SHOWERS AND STORMS BUT TIMING OUT EACH ONE OF THESE BREAKS WILL BE
SOMEWHAT CHALLENGING. IN ADDITION...A LOT OF THE POTENTIAL
FLOODING ISSUES LATER IN THE WEEK WILL DEPEND ON THE AMOUNTS
RECEIVED TODAY.

THE CLOSED UPPER LEVEL LOW ACROSS NEW MEXICO TRANSITIONS INTO AN
OPEN WAVE AND SLOWLY MOVES TO THE NORTHEAST WITH CONTINUED
SOUTHWESTERLY FLOW. THE SOUTHERN STREAM JET INTENSIFIES ACROSS THE
NORTHWESTERN GULF AS THE 500MB TROUGH MOVES INTO THE CENTRAL
PLAINS. THIS WILL PUT CENTRAL ALABAMA IN DIFFLUENT FLOW ALOFT WITH
CONTINUED UPWARD VERTICAL MOTION FOR CONTINUED RAIN CHANCES INTO
THE MIDDLE PART OF THE WEEK. EXPECT ANOTHER ROUND OF 1-2 INCHES
OF PRECIPITATION WILL BE POSSIBLE ACROSS CENTRAL ALABAMA LATE
TUESDAY INTO WEDNESDAY WITH THIS INTENSIFYING UPPER LEVEL JET.

BY THURSDAY AND FRIDAY...ANOTHER CLOSED UPPER LEVEL TROUGH
DEVELOPS ACROSS THE DESERT SOUTHWEST WITH CONTINUED SOUTHWESTERLY
FLOW ALOFT. NUMEROUS SHORTWAVE TROUGHS WILL EJECT FROM THE LOW AND
WILL MOVE ACROSS THE NORTHWESTERN GULF INTO CENTRAL ALABAMA. THIS
WILL KEEP POPS ELEVATED THROUGHOUT THE EXTENDED FORECAST WITH
LITTLE END IN SIGHT TO THIS WET PATTERN. WITH HIGH PRECIPITATION
CHANCES EACH DAY...EXPECT TEMPERATURES WILL RANGE FROM HIGHS IN
THE 70S TO LOW IN THE 60S FOR THE MOST PART THIS WEEK.

RAINFALL AMOUNTS OVER THE NEXT WEEK WILL RANGE FROM 3-6 INCHES
ACROSS CENTRAL ALABAMA. THESE ARE 5-6 DAY TOTAL RAINFALL AMOUNTS
WITH MULTIPLE ROUND OF PRECIPITATION EXPECTED. FOR NOW...HAVE NOT
MENTIONED ANYTHING IN THE HWO REGARDING FLOODING JUST YET DUE TO
THE UNCERTAINTY OF WHEN AND WHERE THE HIGHER AMOUNTS WILL OCCUR.
THERE WILL ALSO BE RISES ALONG STREAMS AND RIVERS ACROSS CENTRAL
ALABAMA. SOME OF THE ENSEMBLE FORECAST INDICATE LOCATIONS ALONG
THE TOMBIGBEE AND BLACK WARRION RIVER BASINS MOVING INTO MINOR
FLOOD STAGE. THESE VALUES ARE BASED ON FORECAST QPF AND THERE IS
STILL SOME UNCERTAINTY AS TO WHERE THESE HIGHER AMOUNTS WILL
OCCUR.

05/MA