National Weather Service Weather Forecast Office

Area Forecast Discussion

820
FXUS64 KHUN 180532 AAC
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1232 AM CDT TUE JUN 18 2013

.UPDATE...
FOR 06Z TAFS

&&

.DISCUSSION...
/ISSUED 859 PM CDT MON JUN 17 2013/
CLUSTERS OF CONVECTION HAVE RECEDED IN INTENSITY WITH LOSS OF
HEATING, AND NO LIGHTNING IS BEING DETECTED IN OUR CWA AT THIS TIME.
RESIDUAL ANVIL PRECIP WILL PERSIST, BUT WE WILL LIKELY SEE A
CONTINUED TO DECLINE IN COVERAGE. WILL MAKE ADJUSTMENTS TO POPS TO
ACCOUNT FOR THIS TREND. CATEGORICAL POPS STILL SEEM JUSTIFIED IN NWRN
AL INTO SRN TN.

JUST TO OUR NORTHWEST AND WEST, CONVECTION HAS ERUPTED NEAR A
DISTINCT MID LEVEL VORTICITY MAX CENTERED NEAR MEMPHIS. JUST TO THE
EAST OF THIS CENTER, CLUSTERS OF +RA PRODUCING STORMS HAVE DEVELOPED
FROM FAR NRN MS INTO SWRN TN. INITIALLY, MUCH OF THIS WILL REMAIN
JUST NW OF THE NW TIP OF AL. WITH TIME HOWEVER, I EXPECT CONVECTION
TO BUILD SWWD AS THE EARLIER NAM SUGGESTS, AND PIVOT NEWD INTO NWRN
AL AND SRN MIDDLE TN. THIS IS MORE LIKELY AFTER 06Z, AND WE`LL SEE
WHAT THE 00Z MODEL RUNS DEPICT IN A SHORT WHILE. 850 MB ANALYSIS AND
00Z SFC GEOSTROPHIC FLOW INDICATE A LLJ OF 20-25KT ACROSS CENTRAL AR
INTO NRN AL. THIS IS PROGGED TO INCREASE TO 30-35KT OVERNIGHT, AND
SHOULD INCREASE MOISTURE TRANSPORT ACROSS THE TN VALLEY. THE THREAT
OF SEVERE WEATHER APPEARS SOMEWHAT MARGINAL GIVEN THE GREATER DEEP
LAYER EFFECTIVE SHEAR IS TO OUR S AND THE COLUMN IS QUITE MOIST.
LOCALLY HEAVY RAINFALL AND A FLASH FLOOD THREAT WILL INCREASE IN
AREAS THAT RECEIVE REPETITIVE STORMS, AND THIS THREAT APPEARS
GREATEST IN MIDDLE INTO SWRN TN AND POSSIBLY FAR NWRN AL OVERNIGHT.
THIS AXIS MAY SHIFT SEWD INTO THE REST OF THE AREA EARLY TUE MORNING.

KULA

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...FLASH FLOOD WATCH FROM 12 AM CDT TUESDAY THROUGH TUESDAY
     EVENING FOR ALZ001>007.

TN...FLASH FLOOD WATCH FROM 12 AM CDT TUESDAY THROUGH TUESDAY
     EVENING FOR TNZ076-096-097.

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE

&&

.AVIATION...
FOR 06Z TAFS... BAND OF THUNDERSTORMS ENTERING NWRN AL WILL APPROACH
KMSL AND PRODUCE MVFR AND POSSIBLY IFR CONDS DUE TO +RA AND LOWERED
CIG. GUSTY WINDS REMAIN PSBL AS WELL. THE STORMS SHOULD REACH THE
KHSV VCNTY BETWEEN 10-14Z PRODUCING SIMILAR CONDITIONS. CONFIDENCE
THEN DECREASES IN THE AREAL EXTENT OF SHRA AND TSRA DURING THE DAY ON
TUESDAY. WILL INCLUDE VCTS AT BOTH SITES UNTIL THE COLD FRONT ARRIVES
DURING THE AFTN HOURS, THEN FOLLOW WITH A VCSH BEHIND THE FRONT.
CIGS SHOULD REMAIN VFR OUTSIDE RAIN AREAS DURING THE PD.

KULA

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR ALZ001>007.

TN...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR TNZ076-096-097.

&&

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.