Area Forecast Discussion
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070
FXUS62 KTAE 130806
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
406 AM EDT MON APR 13 2015

...FLASH FLOOD WATCH CONTINUES FOR MUCH OF THE FLORIDA
PANHANDLE TODAY...

.NEAR TERM [THROUGH TODAY]...
LAST EVENING, A SLOWLY MEANDERING HEAVY RAIN BAND WITH OCCASIONAL
EMBEDDED THUNDERSTORMS PRODUCED PROLIFIC RAIN RATES IN WESTERN
JACKSON COUNTY WITH STORM TOTAL AMOUNTS AS HIGH AS 11". AS OF 07
UTC, THAT PARTICULAR BAND OF RAIN HAS SINCE DIMINISHED, BUT A
LARGER AREA OF RAIN AND EMBEDDED ISO-SCT THUNDERSTORMS IS ABOUT TO
MOVE INTO OUR FORECAST AREA. ONE OF THE CONVECTIVE BANDS IN THAT
LARGER AREA OF RAIN PRODUCED FLASH FLOODING AND OVER 7" OF RAIN IN
THE MOBILE, ALABAMA AREA EARLIER. THE AREA OF RAIN IS SHIFTING
EAST AHEAD OF A MID-LEVEL SHORTWAVE, AND ALSO COINCIDES WITH THE
RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK. AS THE PRIMARY
FORCING MECHANISMS APPEAR TO BE LARGER SCALE FEATURES, THIS AREA
OF RAIN HAS BEEN MORE PROGRESSIVE FROM WEST TO EAST AND THEREFORE
WE EXPECT IT TO TRANSITION ACROSS MUCH OF THE FORECAST AREA TODAY.
POPS WERE BUMPED UP TO CATEGORICAL (80-90%) NORTHWEST OF A CAPE
SAN BLAS, TO TALLAHASSEE, TO TIFTON LINE. HIGH TEMPERATURES WERE
NUDGED DOWN INTO THE MID-70S NORTHWEST TO AROUND 80 SOUTHEAST DUE
TO CLOUDS/RAIN.

THE ENVIRONMENT AHEAD OF THE SHORTWAVE REMAINS LARGELY THE SAME AS
WHEN WE SAW TORRENTIAL RAIN RATES NEAR MARIANNA (PWATS CLOSE TO
RECORDS FOR MID APRIL, SLOW STORM MOTIONS, LOW RADAR ECHO CENTROIDS)
AND THUS LOCALIZED HEAVY RAINFALL WILL REMAIN POSSIBLE - MAINLY NEAR
THE COAST. HEAVY RAIN WORDING WAS INSERTED INTO THE FORECAST. IN THE
WESTERN PANHANDLE (GENERALLY WEST OF THE APALACHICOLA RIVER), WHERE
MORE RAIN FELL EARLIER WE HAVE POSTED A FLASH FLOOD WATCH UNTIL 20
UTC. RAIN RATES OF UP TO 3-4 INCHES PER HOUR WILL BE POSSIBLE ON
ALREADY WET SOILS. THE WATCH MAY NEED TO BE ADJUSTED SPATIALLY OR
TEMPORALLY DEPENDING ON HOW CONVECTION EVOLVES THIS MORNING.
HOWEVER, GIVEN LIGHTER RAIN TOTALS OVER THE PAST 24 HOURS OUTSIDE
THE WATCH AREA, SOILS MAY BE ABLE TO INITIALLY HANDLE HEAVY
RAINFALL.


.SHORT TERM [TONIGHT THROUGH WEDNESDAY]...
UNSETTLED CONDITIONS WILL CONTINUE OVER THE AREA THROUGH THIS
PERIOD. THE UPPER LOW OVER THE SOUTHERN PLAINS WILL OPEN UP AND
EVENTUALLY BE ABSORBED BY AN APPROACHING LONG WAVE TROUGH. A
DOWNSTREAM RIDGE WILL REMAIN IN PLACE OFF THE SOUTHEAST U.S.
COAST. THIS WILL KEEP THE GULF COAST REGION UNDER WSW UPPER FLOW
WITH RIPPLES OF ENERGY PASSING OVERHEAD FROM TIME TO TIME. A
SYNOPTIC FRONT WILL LIFT NORTH OF THE REGION TONIGHT AND TUESDAY
BEFORE SETTLING BACK TOWARD THE FORECAST AREA ON WEDNESDAY. PWAT
WILL REMAIN WELL ABOVE NORMAL. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS CAN BE EXPECTED THROUGH THE PERIOD. WHILE SEVERE
WEATHER CHANCES ARE NOT ALL THAT HIGH, WE WILL NEED TO KEEP AN EYE
ON THE FLASH FLOOD THREAT, ESPECIALLY AFTER SEEING WHAT THIS
RATHER INNOCUOUS PATTERN PRODUCED OVER IN JACKSON COUNTY FL
OVERNIGHT. BROAD RAINFALL TOTALS OF 2-2.5 INCHES ARE EXPECTED
THROUGH WEDNESDAY NORTHWEST OF A LINE FROM PANAMA CITY TO ALBANY
WITH TOTALS EXPECTED TO TAPER OFF TO THE SOUTHEAST. ABUNDANT
CLOUDS WILL KEEP DAYTIME TEMPS LOWER THAN WHAT WE SAW FOR MUCH OF
LAST WEEK. HOWEVER, THEY WILL REMAIN SEVERAL DEGREES ABOVE NORMAL
WITH MAINLY LOWER TO MID 80S EXPECTED. OVERNIGHT LOWS WILL BE
RUNNING SOME 15-18 DEGREES ABOVE NORMAL AND GENERALLY BE IN THE
MID TO UPPER 60S.


.LONG TERM [WEDNESDAY NIGHT THROUGH MONDAY]...
THE UNSETTLED PATTERN WILL CONTINUE OVER THE AREA WITH TEMPERATURE
AND HUMIDITY LEVELS REMAINING ABOVE SEASONAL LEVELS. ANOTHER UPPER
LOW WILL EVENTUALLY MOVE FROM THE SOUTHERN ROCKIES OUT INTO THE
PLAINS BY LATER IN THE WORK WEEK. THIS WILL PROMOTE A TENDENCY FOR
RIDGING DOWNSTREAM OVER THE SOUTHEAST. A SURFACE FRONT WILL ALSO
GENERALLY BE IN THE VICINITY OF THE GULF COAST STATES. TIMING
INDIVIDUAL IMPULSES IN THE EL NINO-INDUCED FAST UPPER FLOW IN THE
SOUTHERN STREAM, AND THEIR IMPACT ON THE EVOLUTION OF SURFACE
FEATURES WILL BE TRICKY, SO WHILE DETAILS ARE UNCLEAR, A CONSENSUS
FOR HIGHER THAN CLIMO POPS AND TEMPS CONTINUES.

&&

.AVIATION...
[THROUGH 06Z TUESDAY] SOME LOW CIGS ARE LIKELY THIS MORNING AT MOST
OF THE TERMINALS, DOWN INTO THE IFR-LIFR RANGE AT TIMES. HOWEVER,
SLOW IMPROVEMENT IS EXPECTED LATER THIS MORNING AND INTO THE
AFTERNOON WITH A TREND TOWARD MVFR-VFR CIGS. AN AREA OF RAIN AND
EMBEDDED ISOLATED THUNDERSTORMS WILL CONTINUE TO BUILD INTO THE
AREA, WITH ALL TERMINALS LIKELY TO SEE RAIN AT SOME POINT. VIS MAY
BE REDUCED AT TIMES IN HEAVIER RAIN.

&&

.MARINE...
OUTSIDE OF THUNDERSTORMS, RELATIVELY LIGHT WINDS AND LOW SEAS WILL
PREVAIL FOR THE NEXT SEVERAL DAYS.

&&

.FIRE WEATHER...
RED FLAG CONDITIONS ARE NOT EXPECTED WITH HIGH RH EXPECTED TO
PREVAIL OVER THE NEXT SEVERAL DAYS. WETTING RAINS ARE LIKELY AND
FUEL MOISTURE LEVELS SHOULD STAY HIGH.

&&

.HYDROLOGY...
EXCEPTIONAL RAINFALL TOTALS OCCURRED OVERNIGHT IN WESTERN JACKSON
COUNTY AND ADJACENT AREAS. EOX AND TLH RADAR BOTH SHOW A BROAD AREA
WITH AT LEAST 2-3" ACCUMULATIONS, AND MAXIMUM VALUES AS HIGH AS 11"
NEAR COTTONDALE AS OF 07 UTC. THIS WAS CONFIRMED BY A PUBLIC REPORT
OF AROUND 11" IN THAT SAME AREA.

THEREFORE, THE ENVIRONMENT TODAY AND INTO THE WEEK WILL FAVOR THE
POSSIBILITY OF VERY HEAVY RAIN RATES IN SLOW MOVING SHOWERS AND
STORMS. SOME LOCALIZED FLOODING WILL BE POSSIBLE DEPENDING ON WHERE
HEAVIER BANDS OF RAIN AND/OR STORMS SET UP. BY WEDNESDAY AFTERNOON,
WE ARE EXPECTING A BROAD AVERAGE OF 1 TO 3 INCHES OF RAIN ACROSS THE
AREA, WITH SLIGHTLY LOWER AMOUNTS IN THE EASTERN FLORIDA BIG BEND.
RAINFALL AMOUNTS THIS HIGH SHOULD CAUSE FLOWS TO INCREASE ON AREA
RIVERS WITH THE POSSIBILITY OF A FEW REACHING FLOOD STAGE. IN
PARTICULAR, THE CHIPOLA RIVER WILL NEED TO BE MONITORED GIVEN THE
AFOREMENTIONED HEAVY RAINFALL IN THE UPPER PORTION OF THE BASIN.

&&

.PRELIMINARY POINT TEMPS/POPS...

TALLAHASSEE   79  69  85  68  83 /  80  40  60  30  60
PANAMA CITY   76  71  80  70  78 /  80  50  60  40  60
DOTHAN        76  66  83  66  82 /  80  50  70  50  70
ALBANY        77  66  85  67  82 /  80  50  70  40  60
VALDOSTA      81  66  85  66  84 /  70  40  60  30  60
CROSS CITY    83  67  85  67  84 /  60  40  40  20  50
APALACHICOLA  77  73  82  72  81 /  60  40  50  30  50

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR CALHOUN-CENTRAL
     WALTON-COASTAL BAY-HOLMES-INLAND BAY-JACKSON-NORTH WALTON-
     SOUTH WALTON-WASHINGTON.

GA...NONE.
AL...NONE.
GM...NONE.
&&

$$

NEAR TERM...LAMERS
SHORT TERM...WOOL
LONG TERM...WOOL
AVIATION...LAMERS
MARINE...WOOL
FIRE WEATHER...LAMERS
HYDROLOGY...LAMERS



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