178
FXUS64 KHUN 160538
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1238 AM CDT WED APR 16 2025
..NEW AVIATION
NEAR TERM
(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 1026 PM CDT TUE APR 15 2025
DRY NW FLOW ALOFT OF 50-60 KNOTS WILL CONTINUE ACROSS THE TN
VALLEY FOR THE REMAINDER OF THE OVERNIGHT PERIOD AND INTO THE DAY
ON WEDNESDAY, AS A MID-LEVEL LOW LIFTS NORTHEASTWARD ACROSS
SOUTHERN QUEBEC AND TRAILING TROUGH AXIS SPREADS EASTWARD ALONG
THE ATLANTIC SEABOARD. AT THE SURFACE, A WEAKENING HIGH WILL
TRAVEL SOUTHEASTWARD FROM CENTRAL OK AND SHOULD BECOME CENTERED
ACROSS NORTHEASTERN MS BY 12Z, RESULTING IN CALM WINDS DURING THE
EARLY MORNING HOURS. THE COMBINATION OF CLEAR SKIES, CALM FLOW AND
DEWPOINTS IN THE M-U 30S WILL SUPPORT RADIATIONAL COOLING, WITH
LOWS GENERALLY EXPECTED TO BE IN THE U30S-L40S. ALTHOUGH SOME
SPOTTY LIGHT MIST/FOG MAY DEVELOP AROUND SUNRISE NEAR LARGE WATER
SOURCES AND IN OUR TYPICALLY FOG-PRONE VALLEYS, CONFIDENCE IN
COVERAGE IS TOO LOW TO INCLUDE IN THE FORECAST AT THIS TIME.
THE LOW-LEVEL RIDGE AXIS WILL TRANSLATE SLOWLY EASTWARD ACROSS
THE TN VALLEY TOMORROW, YIELDING LIGHT/VARIABLE (OR OCCASIONAL
LIGHT NORTHERLY) WINDS THROUGHOUT THE DAY. ALTHOUGH A MINOR
INCREASE IN MID/HIGH-LEVEL CLOUDS MAY OCCUR VERY LATE IN THE DAY,
ABUNDANT SUNSHINE WILL ALLOW AFTERNOON TEMPS TO RECOVER INTO THE
U60S-L70S.
SHORT TERM
(WEDNESDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 1026 PM CDT TUE APR 15 2025
NORTHWEST FLOW ALOFT WILL PERSIST ACROSS THE LOCAL FORECAST AREA
ON WEDNESDAY NIGHT/THURSDAY, BUT SHOULD GRADUALLY WEAKEN INTO THE
40-50 KNOT RANGE AS A RIDGE BUILDS EASTWARD ACROSS THE CENTRAL
PLAINS IN ADVANCE OF AN AMPLIFYING LONGWAVE TROUGH ACROSS THE
WESTERN CONUS. LATEST SHORT RANGE MODEL DATA INDICATES THAT A
SUBTLE MID-LEVEL WAVE WILL EJECT EASTWARD AHEAD OF THE LONGWAVE
TROUGH RESULTING IN A BROAD REGION OF SURFACE PRESSURE FALLS
CENTERED ACROSS WESTERN NE TOMORROW NIGHT, AND THIS (ALONG WITH
THE EASTWARD PROGRESSION OF THE SURFACE ANTICYCLONE INTO THE
CENTRAL APPALACHIANS) WILL INDUCE A LIGHT ESE FLOW BY SUNRISE
THURSDAY MORNING. WITHIN A RAPIDLY STRENGTHENING LOWER
TROPOSPHERIC WARM ADVECTION REGIME TO OUR NORTHWEST, NOCTURNAL
CONVECTION IS PREDICTED TO DEVELOP ALONG A BROAD AXIS FROM THE
MID-MO VALLEY INTO PARTS OF THE MID-SOUTH REGION, AND ALTHOUGH
THERE ARE SOME INDICATIONS THAT THIS REGIME COULD EXTEND INTO
NORTHWEST AL CONFIDENCE IS NOT SUFFICIENTLY HIGH TO INCLUDE
GREATER THAN A 5-10% POP AT THIS POINT. REGARDLESS, AN INCREASE IN
MID/HIGH- LEVEL CLOUDS WILL CONTRIBUTE TO WARMER OVERNIGHT LOWS
IN THE M-U 40S.
DURING THE DAY ON THURSDAY, A STRONGER LEE CYCLONE WILL BECOME
ESTABLISHED ACROSS WESTERN KS AS THE AMPLIFYING WESTERN CONUS
LONGWAVE TROUGH SPREADS SLOWLY EASTWARD. THIS WILL INDUCE A
NOTABLE INCREASE IN SOUTHERLY RETURN FLOW ACROSS THE TN VALLEY,
AND ALTHOUGH A FEW LINGERING WARM ADVECTION-INDUCED SHOWERS MAY
CLIP THE NORTHWESTERN HALF OF THE CWFA IN THE MORNING, DRY
CONDITIONS AND CLEARING SKIES DURING THE AFTERNOON WILL YIELD
HIGHS IN THE M-U 70S. MODERATELY STRONG SOUTHERLY FLOW WILL
PERSIST ON THURSDAY NIGHT/FRIDAY AS THE INITIAL LEE CYCLONE
WEAKENS AND LIFTS NORTHEASTWARD INTO THE LAKE MI VICINITY, BUT
WITH LIMITED NORTHWARD RETURN OF LOW-LEVEL MOISTURE LOWS THURSDAY
NIGHT WILL BE IN THE M-U 50S FOLLOWED BY HIGHS IN THE L-M 80S
FRIDAY.
LATE IN THE DAY ON FRIDAY AND INTO FRIDAY NIGHT, RENEWED SURFACE
CYCLOGENESIS IS PREDICTED TO OCCUR ACROSS WESTERN TX, AS A
SHORTWAVE DISTURBANCE WITHIN THE BASE OF THE WESTERN CONUS TROUGH
BEGINS TO AMPLIFY OVER THE FOUR CORNERS REGION. THIS WILL
EFFECTIVELY FORCE THE COLD FRONT (TRAILING THE INITIAL LOW) TO
STALL WELL TO OUR NORTHWEST, AND SHOULD FORCE THE DEVELOPMENT OF
WIDESPREAD ELEVATED CONVECTION ALONG THE COOL SIDE OF THE BOUNDARY
(FROM SOUTHWESTERN OK/NORTHWESTERN TX INTO OH). ACROSS OUR CWFA,
RICHER LOW-LEVEL MOISTURE WILL FINALLY RETURN FRIDAY EVENING, WITH
AN EXPANSIVE DECK OF LOW STRATUS CLOUDS RESULTING IN LOWS IN THE
U50S-M60S SATURDAY MORNING.
LONG TERM
(SATURDAY THROUGH TUESDAY)
ISSUED AT 1026 PM CDT TUE APR 15 2025
LATEST EXTENDED RANGE MODEL GUIDANCE SUGGESTS THAT AN AMPLIFYING
SHORTWAVE (EMBEDDED WITHIN THE BASE OF A BROADER LONGWAVE TROUGH
TO OUR WEST) WILL ADVANCE EASTWARD ACROSS THE SOUTHERN ROCKIES ON
SATURDAY, BEFORE ACQUIRING A SHARP NEGATIVE TILT AS IT EJECTS
NORTHEASTWARD FROM THE SOUTHERN HIGH PLAINS INTO THE SOUTHWESTERN
GREAT LAKES SATURDAY NIGHT-SUNDAY NIGHT. AT THE SURFACE, MODERATE
SOUTHERLY FLOW WILL CONTINUE ACROSS THE TN VALLEY AS THE RELATED
SURFACE LOW TRACKS SLOWLY EASTWARD ACROSS NORTHWEST TX SATURDAY,
BEFORE DEEPENING AND LIFTING NORTHEASTWARD INTO SOUTHWESTERN MO
SATURDAY NIGHT AND INTO THE GREAT LAKES BY SUNDAY NIGHT.
WIDESPREAD ANAFRONTAL CONVECTION WILL REMAIN FOCUSED WELL TO OUR
NORTH/WEST (IN THE VICINITY OF A STATIONARY FRONT) ON
SATURDAY/SATURDAY NIGHT, ALTHOUGH OUTFLOW EMANATING FROM THIS
ACTIVITY MAY SNEAK INTO NORTHWEST AL EARLY SUNDAY MORNING PERHAPS
INITIATING A FEW SHOWERS/STORMS PRIOR TO SUNRISE.
PRESENT INDICATIONS ARE THAT A QLCS WILL GRADUALLY DEVELOP LATE
SUNDAY MORNING IN THE VICINITY OF A PREFRONTAL SURFACE TROUGH AS
IT TRACKS EASTWARD ACROSS MO/AR AND INTO THE MID-SOUTH REGION.
ALTHOUGH THERE ARE NOTABLE DIFFERENCES IN TIMING (LIKELY RELATED
TO THE STRONGER DEEP-LAYER FORCING FOR ASCENT WITH THE MID-LEVEL
TROUGH BYPASSING OUR REGION TO THE NORTH), THE PREFRONTAL TROUGH
WILL EVENTUALLY BE OVERTAKEN BY THE COLD FRONT, WITH THIS FEATURE
CONTINUING TO FOCUS THE DEVELOPMENT OF CONVECTION AS IT SPREADS
SLOWLY SOUTHEASTWARD ACROSS OUR CWFA (LIKELY AT SOME POINT LATE
SUNDAY NIGHT/EARLY MONDAY MORNING). MID-LEVEL SW FLOW OF 45-55
KNOTS WILL PROVIDE SUFFICIENT DEEP-LAYER SHEAR FOR STORM
ORGANIZATION, BUT WITH ONLY MINOR VEERING IN THE SURFACE-500 MB
LAYER AND SHEAR ALIGNED NEARLY PARALLEL TO THE SURFACE BOUNDARY,
MULTICELL STORM CLUSTERS WOULD BE THE FAVORED STORM MODE. WITH
DEWPOINTS IN THE U50S-M60S BENEATH WEAK LAPSE RATES ALOFT
GENERATING CAPE OF 250-750 J/KG, MARGINALLY SEVERE WIND AND HAIL
WILL BE CAPABLE WITH THESE CLUSTERS, AND ALTHOUGH THE LOW LEVEL
JET WILL CERTAINLY NOT BE AS STRONG AS IT COULD BE THIS TIME OF
YEAR (30-40 KNOTS), SUFFICIENT LOW-LEVEL SHEAR WILL EXIST FOR A
FEW BRIEF TORNADOES. CONVECTION WILL COME TO AN END AS THE FRONT
DRIFTS FURTHER SOUTHEASTWARD MONDAY, WITH A SLIGHTLY COOLER/DRIER
AIRMASS INFILTRATING THE REGION MONDAY NIGHT/TUESDAY.
AVIATION
(06Z TAFS)
ISSUED AT 1238 AM CDT WED APR 16 2025
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AT BOTH
TERMINALS WITH CLEAR SKIES AND LIGHT/VARIABLE WINDS.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...70
SHORT TERM....70
LONG TERM....70
AVIATION...25
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