879
FXUS64 KHUN 201645
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1145 AM CDT MON APR 20 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1030 AM CDT MON APR 20 2026
- AN UNSETTLED PATTERN WILL DEVELOP THIS WEEKEND BRINGING CHANCES
(50-70%) FOR RAIN AND STORMS.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1030 AM CDT MON APR 20 2026
IN THE MID/UPPER-LEVELS, NORTH-NORTHWEST FLOW OF 40-50 KNOTS WILL
CONTINUE ACROSS THE TN VALLEY TODAY, BUT SHOULD QUICKLY DROP INTO
THE 10-20 KNOT RANGE BY EARLY TUESDAY MORNING AS A LONGWAVE
TROUGH ADVANCES EASTWARD ACROSS EASTERN CANADA/NORTHEASTERN CONUS
AND A LOW-AMPLITUDE RIDGE (IN IT'S WAKE) TRACKS FROM THE SOUTHERN
HIGH PLAINS INTO THE LOWER MS VALLEY. AT THE SURFACE, A WEAK RIDGE
OF HIGH PRESSURE WILL REMAIN CENTERED ACROSS CENTRAL PORTIONS OF
MS/AL TODAY, WITH A STRONGER ANTICYCLONE PREDICTED TO DROP
SOUTHEASTWARD ACROSS THE EASTERN GREAT LAKES. ALTHOUGH A FEW LIGHT
SHOWERS (ORIGINATING FROM OVERCAST ALTOSTRATUS CLOUDS) MAY OCCUR
ACROSS PORTIONS OF THE SOUTHERN APPALACHIANS TODAY (ALONG AND
NORTH OF A NORTHEASTERLY WIND SHIFT AXIS RELATED TO THE GREAT
LAKES HIGH), WE DO NOT EXPECT THIS ACTIVITY TO IMPACT OUR CWFA.
THUS, MOSTLY SUNNY SKIES WILL YIELD HIGHS APPROXIMATELY 10-12
DEGREES WARMER (COMPARED TO YESTERDAY) WITH AFTERNOON READINGS IN
THE LOWER 70S (ELEVATED TERRAIN) AND M-U 70S IN THE VALLEY.
OVERNIGHT, CLEAR SKIES AND LIGHT-VARIABLE WINDS WILL ONCE AGAIN
PROVE EFFECTIVE FOR RADIATIONAL COOLING, BUT WITH GRADUAL
MODIFICATION OF BOUNDARY LAYER DEWPOINTS EXPECTED TO OCCUR
THROUGHOUT THE DAY, LOWS WILL BE A FEW DEGREES WARMER (M-U 40S).
NEVERTHELESS, BRIEF DEVELOPMENT OF PATCHY FOG CAN BE EXPECTED IN A
FEW OF OUR NORMALLY FOG-PRONE LOCATIONS AFTER MIDNIGHT.
SHORT TERM
(TUESDAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 1030 AM CDT MON APR 20 2026
SHORT RANGE MODEL CONSENSUS SUGGESTS THAT A 500-MB SHORTWAVE
RIDGE WILL TRANSLATE EASTWARD ACROSS THE TN VALLEY TOMORROW, WITH
A WEAK TROUGH EXPECTED TO DIG FROM THE SOUTHERN PLAINS INTO THE
NORTH FL FROM TUESDAY INTO WEDNESDAY NIGHT. IN THE LOW-LEVELS, WE
WILL REMAIN UNDER THE INFLUENCE OF A WEAKENING AREA OF HIGH
PRESSURE DRIFTING SOUTHEASTWARD OFF THE MID-ATLANTIC COAST FOR
MUCH OF THE SHORT TERM PERIOD, AS THE WESTERN PERIPHERY OF THE
SURFACE RIDGE IS PREDICTED TO REMAIN INTACT ACROSS THE CENTRAL
GULF COAST STATES. THUS, ALTHOUGH LIGHT SOUTHWESTERLY RETURN FLOW
WILL CONTRIBUTE TO PROGRESSIVELY WARMER TEMPERATURES (HIGHS
RETURNING TO THE U70S-L80S AND LOWS RETURNING TO THE L-M 50S),
DEWPOINTS WILL ONLY GRADUALLY CLIMB INTO THE U40S-L50S BY
WEDNESDAY AND WEDNESDAY NIGHT. PRESENT INDICATIONS ARE THAT RAIN
AND THUNDERSTORMS RELATED TO ELEVATED WARM/MOIST ADVECTION ON THE
WESTERN EDGE OF THE LOW-LEVEL RIDGE WILL REMAIN FOCUSED ACROSS TX
TODAY AND TONIGHT, BEFORE THIS REGIME GRADUALLY BEGINS TO SPREAD
EASTWARD THROUGH THE LOWER MS VALLEY AND PERHAPS INTO THE CENTRAL
GULF COAST STATES DURING THE SHORT TERM PERIOD. ALTHOUGH SOLUTIONS
FROM SOME OF THE CAMS (MOST NOTABLY THE RRFS-EMC) INDICATE THAT
WEAK CELLULAR CONVECTION MAY IMPACT PORTIONS OF MS/AL/GA ON
WEDNESDAY AFTERNOON/EVENING, THIS WOULD MOST LIKELY OCCUR ACROSS
THE SOUTHERN PORTIONS OF THESE STATES (WHERE DEWPOINTS WILL BE A
BIT HIGHER), AND WE WILL MAINTAIN A DRY FORECAST FOR OUR CWFA AT
THIS TIME.
LONG TERM
(THURSDAY THROUGH SUNDAY)
ISSUED AT 856 PM CDT SUN APR 19 2026
UPPER LEVEL RIDGING BEGINS TO MOVE INTO THE SOUTHEAST DURING THE
SECOND HALF OF THE WORK WEEK. WITH SFC HIGH PRESSURE LOCATED
ACROSS GA/SC, SOUTHERLY FLOW WILL ADVECT IN A WARM AND MOIST
AIRMASS INTO THE TENNESSEE VALLEY. LOCALLY, THIS RESULTS IN A
GRADUAL WARMING TREND IN TEMPERATURES, BUT ALSO A MUCH MORE
NOTICEABLE INCREASE IN DEWPOINTS. AFTERNOON HIGHS THURSDAY AND
FRIDAY RISE INTO THE MID 80S WITH DEWPOINTS INCREASING FROM THE
LOWER 50S ON THURSDAY TO LOWER 60S BY FRIDAY EVENING. THE DRY
PATTERN COMES TO AN END BY THIS WEEKEND AS TROUGHING TO OUR WEST
SHIFTS EASTWARD ALLOWING FOR SEVERAL SHORTWAVES TO RIPPLE THROUGH
THE LOCAL FORECAST AREA. THE FIRST OF THESE DISTURBANCES ARRIVES
FRIDAY EVENING/SATURDAY MORNING, WHICH WILL BRING A MEDIUM CHANCE
(45-65%) OF SHOWERS AND THUNDERSTORMS TO THE AREA. A MORE
SUBSTANTIAL SYSTEM MOVES THROUGH THIS WEEKEND AND WILL BE
SOMETHING TO KEEP AN EYE ON FOR SEVERE STORMS. JOINT PROBABILITIES
OF SHEAR GREATER THAN 30 KNOTS AND CAPE EXCEEDING 1000 J/KG HAVE
INCREASED TO AROUND 30 PERCENT. VARIOUS MACHINE LEARNING
ALGORITHMS ALSO SHOW LOW PROBABILITIES OF SEVERE STORMS. AT THIS
TIME IT IS TOO EARLY TO PIN DOWN AN EXACT TIMEFRAME OF THE MOST
LIKELY PERIOD FOR SHOWERS AND THUNDERSTORMS WILL BE 6-7 DAYS OUT.
HOWEVER, IT IS APRIL AND THIS IS TYPICALLY ONE OF OUR MOST ACTIVE
MONTHS FOR SEVERE STORMS. CHECK BACK FOR UPDATES AS DETAILS FOR
THE WEEKEND BECOME MORE CLEAR.
AVIATION
(18Z TAFS)
ISSUED AT 1145 AM CDT MON APR 20 2026
VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...70
SHORT TERM....70
LONG TERM....GH
AVIATION...HC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page