387
FXUS64 KHUN 300450
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1150 PM CDT SUN JUN 29 2025
..NEW AVIATION
NEAR TERM
(THIS EVENING THROUGH MONDAY)
ISSUED AT 1028 PM CDT SUN JUN 29 2025
IN THE MID/UPPER-LEVELS, A SUBTROPICAL RIDGE (CENTERED ACROSS THE
NORTHWEST GULF COAST) HAS EXPANDED NORTHEASTWARD INTO THE TN
VALLEY AND WILL CONTINUE TO PROVIDE LIGHT STEERING CURRENTS
OVERNIGHT, BEFORE STRONGER WESTERLY FLOW BECOMES ESTABLISHED
TOMORROW IN RESPONSE TO AN AMPLIFYING SHORTWAVE TROUGH DIGGING
INTO THE UPPER MS VALLEY/WESTERN GREAT LAKES. THIS WILL OCCUR AS
SOUTHWESTERLY FLOW IN THE LOWER TROPOSPHERE GRADUALLY BECOMES MORE
PRONOUNCED WITHIN A CONTRACTING PRESSURE GRADIENT ALONG THE
WESTERN EDGE OF THE BERMUDA HIGH TO OUR EAST-SOUTHEAST.
LOCAL RADAR DATA SUGGESTS THAT RESIDUAL LIGHT RAIN (STEMMING FROM
WIDESPREAD CONVECTION EARLIER TODAY) CONTINUES TO QUICKLY
DISSIPATE ACROSS OUR CWFA AS OF THIS WRITING, AND WITH PARTIAL
CLEARING OF THE MID/HIGH-LEVEL DEBRIS CLOUDS OCCURRING IN PORTIONS
OF THE REGION, PATCHY MIST/FOG MAY DEVELOP IN A FEW LOCATIONS AS
TEMPERATURES FALL INTO THE U60S-L70S. TO OUR WEST-NORTHWEST,
CONVECTION (INITIATED BY OUTFLOW FROM A LARGE COMPLEX OF STORMS
ACROSS SOUTHERN MO EARLIER THIS EVENING) CONTINUES TO SPREAD
SOUTHEASTWARD ACROSS NORTHERN AR, WITH DEVELOPMENT OF ADDITIONAL
THUNDERSTORMS OCCURRING IN THE DOWNSTREAM AIRMASS ACROSS THE MID-
SOUTH. ALTHOUGH THUNDERSTORMS DIRECTLY RELATED TO THE OUTFLOW WILL
TEND TO SLOWLY DISSIPATE LATER THIS EVENING, DEVELOPMENT OF
ISOLATED CELLS IN THE DOWNSTREAM AIRMASS WILL LIKELY CONTINUE,
WITH SOME OF THIS ACTIVITY POTENTIALLY IMPACTING THE FAR
NORTHWESTERN PORTION OF OUR FORECAST AREA AS EARLY AS 6-8Z. AS THE
REMNANT OUTFLOW BOUNDARY PROGRESSES FURTHER SOUTHEASTWARD,
REDEVELOPMENT OF STORMS MAY ALSO OCCUR ALONG THIS FEATURE AS IT
BEGINS TO INTERACT WITH A PREEXISTING MESOSCALE CONFLUENCE AXIS
ACROSS NORTHERN MS/SOUTHWESTERN TN/NORTHWEST AL, BUT THIS WOULD
LIKELY NOT OCCUR UNTIL THE 10-14Z TIMEFRAME. ENVIRONMENTAL
PARAMETERS SUGGEST THAT ANY STORMS IN OUR REGION WILL BE SUB-
SEVERE, BUT CAPABLE OF PRODUCING FREQUENT LIGHTNING AND EXCESSIVE
RAINFALL (GIVEN PWAT VALUES OF 2-2.1").
THE EXTENT OF THUNDERSTORM ACTIVITY IN OUR REGION AROUND SUNRISE
TOMORROW MORNING WILL HAVE A SIGNIFICANT IMPACT ON CONVECTIVE
TRENDS LATER IN THE DAY, BUT OUR GENERAL EXPECTATION IS FOR A
LIMITED COVERAGE OF STORMS (PRIMARILY ACROSS NORTHWEST AL) THAT
WILL TEND TO SPREAD SOUTHEASTWARD INTO CENTRAL AL WITH TIME.
SHOULD THIS OCCUR, SUFFICIENT WARMING/DESTABILIZATION WILL TAKE
PLACE LATE TOMORROW MORNING TO SUPPORT RAPID REDEVELOPMENT OF
STORMS ALONG MULTIPLE MESOSCALE BOUNDARIES IN THE REGION BETWEEN
16-18Z, THAT WILL SPREAD EAST-SOUTHEASTWARD AND OUT OF THE AREA BY
SUNSET (IF NOT SOONER). IN SIMILAR FASHION TO TODAY, MLCAPE OF
2000-2500 J/KG MAY DEVELOP IN PORTIONS OF THE REGION WHERE TEMPS
REACH THE M-U 80S, AND THIS COULD RESULT IN GUSTY WINDS UP TO
40-50 MPH WITH A FEW OF THE CELLS. HOWEVER, LIGHTNING AND HEAVY
RAIN WILL BE THE MAIN CONCERNS.
SHORT TERM
(MONDAY NIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 1028 PM CDT SUN JUN 29 2025
LATEST MODEL DATA STILL INDICATES THAT A COLD FRONT (RELATED TO
AN AMPLIFYING TROUGH IN THE NORTHERN STREAM) WILL LIKELY EXTEND
FROM A DEVELOPING FRONTAL WAVE (OVER THE LOWER GREAT LAKES)
SOUTHWESTWARD THROUGH THE MID-MS VALLEY AND INTO SOUTHERN OK AT 0Z
TUESDAY. ALTHOUGH WITH VARYING DEGREES OF INTENSITY AND COVERAGE,
NEARLY ALL NWP GUIDANCE SUGGESTS THAT BROKEN CLUSTERS OF STORMS
WILL SPREAD EAST-SOUTHEASTWARD OFF THE COLD FRONT TOMORROW
EVENING, WITH SOME OF THIS ACTIVITY PREDICTED TO REACH OUR
FORECAST AREA BETWEEN 6-12Z TUESDAY. THIS CONVECTION SHOULD BE
SUB-SEVERE, BUT MAY CARRY A SLIGHTLY HIGHER RISK FOR GUSTY OUTFLOW
WINDS (GIVEN STRENGTHENING ENVIRONMENTAL FLOW) AS WELL AS
LIGHTNING AND HEAVY RAIN. DEPENDING ON THE EXTENT AND COVERAGE OF
PRECIPITATION (AND CONVECTIVE DEBRIS CLOUDS) TUESDAY MORNING,
REDEVELOPMENT OF STORMS SHOULD OCCUR ONCE AGAIN BY LATE MORNING AS
THE INITIAL FRONTAL WIND SHIFT ENTERS THE NORTHWEST PORTION OF
THE FORECAST AREA. PRESUMING THAT LINGERING IMPACTS FROM MORNING
PRECIPITATION WILL BE ERODED BY TUESDAY AFTERNOON, A MINOR
INCREASE IN BOTH CAPE AND MID-LEVEL WNW FLOW MAY SUPPORT
DEVELOPMENT OF A SMALL BUT ORGANIZED STORM CLUSTER/MCS AS THE WIND
SHIFT AXIS SPREADS SOUTHEASTWARD, AND THIS REPRESENTS THE
TIMEFRAME OF GREATEST CONCERN FOR A MORE WIDESPREAD DAMAGING WIND
RISK.
PRESENT INDICATIONS ARE THAT THUNDERSTORMS WILL BE ENDING ACROSS
THE SOUTHEASTERN PORTION OF THE FORECAST AREA EARLY TUESDAY
EVENING, AS LIGHT NNE WINDS BEGIN TO ADVECT A SLIGHTLY DRIER
AIRMASS INTO THE REGION ORIGINATING FROM A MODIFIED NORTH PACIFIC
AIRMASS ACROSS THE CENTRAL PLAINS. IF THE SOUTHWARD ADVECTION OF
DRIER AIR IS DELAYED, THEN A FEW RESIDUAL SHOWERS AND STORMS WILL
BE POSSIBLE ACROSS THE SOUTHEASTERN COUNTIES THROUGH THE DAY ON
WEDNESDAY, BUT AT THIS POINT POPS ARE QUITE LOW FOR THIS SCENARIO
(5-10%). HIGHS WILL REMAIN IN THE M-U 80S BOTH TUESDAY/WEDNESDAY,
BUT LOWS WILL FALL BACK INTO THE MID 60S BY THURSDAY MORNING.
LONG TERM
(THURSDAY THROUGH SUNDAY)
ISSUED AT 1028 PM CDT SUN JUN 29 2025
LIGHT-MODERATE NORTHWEST FLOW ALOFT WILL PERSIST ACROSS THE TN
VALLEY ON THURSDAY/THURSDAY NIGHT, BUT SHOULD DIMINISH AND VEER TO
THE NORTH ON FRIDAY/FRIDAY NIGHT AS A STRENGTHENING SUBTROPICAL
RIDGE (TO OUR SOUTHWEST) BUILDS NORTHEASTWARD INTO THE LOWER MS
VALLEY. WITH LOW-LEVEL FLOW EXPECTED TO BE DICTATED BY A SURFACE
HIGH TO OUR NORTHEAST, WE WILL MAINTAIN A DRY FORECAST WITH HIGHS
WARMING BACK INTO THE LOWER 90S BY FRIDAY. THE LOW-LEVEL RIDGE
WILL BEGIN TO SHIFT EASTWARD INTO THE WESTERN NORTH ATLANTIC BY
SATURDAY/SUNDAY, RESULTING IN A LIGHT SOUTHEAST FLOW ACROSS OUR
REGION. HOWEVER, MOISTURE RETURN MAY BE IMPACTED TO SOME EXTENT BY
A DEVELOPING UPPER LOW AND SURFACE WAVE SOMEWHERE IN THE VICINITY
OF NORTH/CENTRAL FL, AND THIS SHOULD KEEP HEAT INDEX VALUES IN
CHECK AS AFTERNOON TEMPS RETURN TO THE L-M 90S. WITH A GRADUAL
INCREASE IN BOTH ATMOSPHERIC WATER CONTENT AND CAPE ANTICIPATED
THIS WEEKEND, A FEW AFTERNOON SHOWERS AND STORMS MAY OCCUR BOTH
DAYS (ESPECIALLY IN THE HIGHER TERRAIN OF NORTHEAST AL).
AVIATION
(06Z TAFS)
ISSUED AT 1150 PM CDT SUN JUN 29 2025
THERE HAVE BEEN NO SIGNIFICANT CHANGES TO PREVIOUS AVIATION
FORECAST REASONING, AS PARTIAL CLEARING OF MID/HIGH-LVL CONVECTIVE
DEBRIS CLOUDS MAY SUPPORT THE DEVELOPMENT OF LGT BR/FG THRU 12Z.
OTHERWISE, THE NEXT CONCERN WILL BE CONVECTION, WHICH MAY
REDEVELOP INVOF A REMNANT OUTFLOW BOUNDARY (ACROSS WESTERN
PORTIONS OF THE FORECAST AREA) AS EARLY AS 10-12Z. HOWEVER, GIVEN
THE VARIABILITY OF MODEL SOLUTIONS (AND OVERALL LEVEL OF
UNCERTAINTY) REGARDING THIS SCENARIO, WE HAVE CHOSEN NOT TO
INCLUDE TSRA IN THE TAFS DURING THE EARLY MORNING HOURS, BUT
RESERVED PROB30 GROUPS FOR THE 16-22Z TIMEFRAME WHICH APPEARS TO
BE THE WINDOW WHEN STORMS WILL BE MOST PREVALENT. ASIDE FROM
IMPACTS FROM EARLY MORNING FOG AND AFTERNOON TSRA, CONDS WILL
REMAIN VFR WITH LIGHT PREVAILING FLOW FROM THE SW.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...70/DD
AVIATION...70/DD
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