418
FXUS64 KHUN 171721
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1221 PM CDT SUN MAY 17 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1133 AM CDT SAT MAY 17 2026
- A SIGNIFICANT WARMING TREND TODAY INTO EARLY NEXT WEEK WITH
HIGHS IN THE UPPER 80S TO LOWER 90S.
- LOW CHANCES (20-30%) FOR A FEW THUNDERSTORMS IN FAR NORTHEAST
ALABAMA TODAY AND ON MONDAY AFTERNOONS.
- LOW TO MEDIUM CHANCES (20-50%) FOR SHOWERS AND THUNDERSTORMS
RETURNING LATE TUESDAY AFTERNOON INTO TUESDAY EVENING. THEN
MEDIUM TO HIGH (40-80%) CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH FRIDAY.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1133 AM CDT SUN MAY 17 2026
CLEAR SKIES ARE IN PLACE ACROSS NORTHERN ALABAMA AND SOUTHERN
MIDDLE TENNESSEE AT 11 AM CDT. UNDERNEATH A BUILDING UPPER LEVEL
RIDGE, TEMPERATURES HAVE CLIMBED INTO THE 82 TO 85 DEGREE RANGE
ALREADY.
MODELS SHOW AN UPPER LEVEL TROUGH AXIS IN PLACE ON THE NW SIDE OF
THE UPPER RIDGE LOCATED ROUGHLY OVER WEST CENTRAL GEORGIA. A
TROUGH AXIS EXTENDS SE FROM THIS FEATURE IN MODEL GUIDANCE INTO SE
GEORGIA. SATELLITE IMAGERY SHOWS THIS FEATURE AS WELL. MOST
GUIDANCE DEVELOPS CONVECTION ALONG AND EAST OF THIS TROUGH AXIS
LATER TODAY, ESPECIALLY IN THE AFTERNOON/EARLY EVENING HOURS.
LEAVING ONLY A 5 TO 14 PERCENT CHANCE IN THE FORECAST OF ANY
PRECIPITATION NEAR THE AL/GA BORDER IN OUR AREA.
CLOUD COVER SHOULD INCREASE THOUGH IN THE FORM OF A CUMULUS DECK
NEAR THE AL/GA BORDER LATER TODAY. THIS SHOULD KEEP HIGHS JUST A
TAD LOWER IN THE 87 TO 90 DEGREE RANGE IN NE ALABAMA. FURTHER
WEST, HIGHS IN THE 88 TO 93 DEGREE RANGE ARE EXPECTED. BE SURE TO
HYDRATE IF WORKING OUTSIDE OR PLAYING SPORTS.
CONSISTENT MOIST SOUTHERLY TO SLIGHTLY SOUTH-SOUTHWESTERLY FLOW
WILL CONTINUE TONIGHT. THIS WILL SLOWLY BRING MORE LOW LEVEL
MOISTURE NORTHWARD FROM THE GULF OF AMERICA INTO THE AREA. LOWS
SHOULD BE WARMER AS A RESULT, ONLY DROPPING INTO THE MID TO UPPER
60S IN MOST LOCATIONS.
SHORT TERM
(MONDAY THROUGH WEDNESDAY)
ISSUED AT 1133 AM CDT SUN MAY 17 2026
A STRONG LONGWAVE TROUGH AXIS FOR THIS TIME OF YEAR WILL PUSH EAST
FROM THE DESERT SOUTHWEST INTO THE CENTRAL PLAINS AREA ON MONDAY.
THE UPPER RIDGE OVER THE AREA CONTINUES TO HOLD STRONG THOUGH
OVER THE SOUTHEAST. HOWEVER, LOW LEVEL MOISTURE ADVECTION WILL
CONTINUE AND AREAS WEST OF I-65 WILL LIKELY SEE A LOT OF
SUNSHINE. THIS SHOULD ALLOW HIGHS TO CLIMB BACK INTO THE UPPER 80S
AND LOWER 90S AGAIN ON MONDAY. FURTHER EAST, MODELS HINT AT A
WEAK LOW LEVEL MOISTURE CONVERGENCE BOUNDARY SETTING UP OVER FAR
EASTERN ALABAMA FORMED FROM CONVECTION THE DAY BEFORE IN
GEORGIA. THIS COULD BE A FOCUS A LOW CHANCE (20-30 PERCENT
COVERAGE) OF CONVECTIVE DEVELOPMENT IN THE AFTERNOON/EARLY EVENING
BEFORE DISSIPATING. SBCAPE IS NOT BAD (800 TO 1500 J/KG) IN MOST
GUIDANCE (A BIT HIGHER IN SOME). HOWEVER, SHEAR CONTINUES TO BE
WEAK AND LAPSE RATE AROUND CLOSER TO 6.5 DEGREE/KM IN THE
AFTERNOON. THIS LOOKS LIKE GENERAL THUNDERSTORM PARAMETERS. IF
SBCAPE CLIMBS TO BETWEEN 2000 AND 3000 J/KG IN FUTURE MODELS RUNS
OR LAPSE RATES STEEPEN, THEN A MARGINAL SEVERE DOWNBURST THREAT
COULD MATERIALIZE.
BY MONDAY NIGHT, SOUTHWESTERLY FLOW DEEPENS. THIS SHOULD HELP TO
BRING EVEN HIGHER DEWPOINTS INTO THE AREA AND KEEP LOWS FROM
DROPPING BELOW THE 65 TO 70 DEGREE RANGE IN MOST AREAS (EXCEPTION
BEING THE VALLEY AREAS OF NE ALABAMA).
MOST GUIDANCE KEEPS CONVECTION WEST OF THE AREA ON TUESDAY (EXCEPT
THE ECMWF SUITE) DUE TO THE CONTINUING STRENGTH OF THE UPPER
LEVEL RIDGE OVER THE SOUTHEAST. WE WILL HAVE MORE CLOUD COVER
AROUND THOUGH, KEEPING HIGHS FROM CLIMBING BACK INTO THE 89 TO 93
DEGREE RANGE. HIGHS STILL CLIMB INTO THE 85 TO 90 DEGREE RANGE
GIVEN THE WARM 925 MB TEMPERATURES SHOWN IN GUIDANCE. ONLY KEPT A
LOW CHANCE (20-30%) OF SHOWERS AND THUNDERSTORMS IN THE FORECAST
IN NW ALABAMA IN THE AFTERNOON ON TUESDAY.
MODELS SEEM TO CONVERGE ON SHOWING THE UPPER RIDGING REALLY
WEAKENING AND SLIDING FURTHER EAST TUESDAY NIGHT INTO WEDNESDAY.
LOW TO MEDIUM CHANCES (20-50%) OF SHOWERS AND THUNDERSTORMS PUSH
INTO THE AREA AS A RESULT. SHEAR REMAINS WEAK IN GUIDANCE, BUT
FAIRLY UNSTABLE CONDITIONS (SBCAPE 1000 TO 2000 J/KG) BUILDS OVER
THE AREA DURING THE DAY ON WEDNESDAY. GIVEN INSTABILITY PARAMETERS
AND SHEAR CLIMBING TO BETWEEN 20 AND 25 KNOTS, A MARGINAL THREAT
OF STRONG TO SEVERE THUNDERSTORMS COULD DEVELOP, BUT CONFIDENCE IN
THAT IS VERY LOW.
LONG TERM
(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 1045 PM CDT SAT MAY 16 2026
UPPER LEVEL ZONAL FLOW ON WEDNESDAY LOOKS TO EVENTUALLY TURN INTO
SOUTHWEST FLOW ALOFT THROUGH LATE WEEK. IN ADDITION, A SERIES OF
SHORTWAVES ARE SHOWN BY GUIDANCE TO MOVE ALONG THIS FLOW PATTERN OVER
THE SOUTHEAST FROM MID TO LATE WEEK. MEANWHILE, A SURFACE COLD FRONT
WILL APPROACH THE TENNESSEE VALLEY ON WEDNESDAY, PASSING JUST TO OUR
SOUTH BY THURSDAY, THEN STALL OVER THE SOUTHEAST THROUGH SATURDAY.
OVERALL, EXPECT A WET PATTERN FROM WEDNESDAY THROUGH SATURDAY!
LOOKING AT THE POTENTIAL FOR STORMS, WHILE INSTABILITY IS SUFFICIENT
FOR DEVELOPMENT, BULK SHEAR VALUES (PARTICULARLY ON WEDNESDAY) ARE
LOW. VALUES ON WEDNESDAY ARE GENERALLY AROUND 10 KTS OR LESS.
GUIDANCE THEN SUGGESTS BULK SHEAR VALUES WILL BE LESS THAN 30 KNOTS
THROUGH AT LEAST FRIDAY. THEREFORE, NOT ANTICIPATING SEVERE STORMS AT
THIS TIME.
EVEN WITH LOW CONFIDENCE IN THE POTENTIAL FOR ANY SEVERE WEATHER,
MODEL PWATS ON WEDNESDAY GENERALLY RANGE BETWEEN 1.6-1.8 INCHES BY
WEDNESDAY AND THIS LOOKS TO PERSIST INTO THE WEEKEND. WHEN COMPARED
WITH BMX SOUNDING CLIMATOLOGY (IN THE AFTERNOON), THIS RANGE IS OVER
THE 90TH PERCENTILE. THEREFORE, SHOWERS AND STORMS WILL BE EFFICIENT
RAINFALL PRODUCERS. IN ADDITION, MODEL SOUNDINGS SHOW LOW CORFIDI
DOWNSHEAR VALUES ON WEDNESDAY, INDICATIVE OF SLOW-MOVING
SHOWERS/STORMS AS WELL AS THE POTENTIAL FOR BACKBUILDING/TRAINING
STORMS (INCREASING THE POTENTIAL FLOOD THREAT). FURTHERMORE, WITH
SEVERAL DAYS OF ELEVATED MOISTURE AND MEDIUM TO HIGH CHANCES OF
SHOWERS/STORMS, WE'LL NEED TO CONTINUE TO KEEP AN EYE ON THE
POTENTIAL FOR FLASH FLOODING BY LATE WEEK, ESPECIALLY FOR AREAS THAT
SEE CONSISTENT AND HEAVIER RAINFALL DURING THIS TIME. IT HAS BEEN
FAIRLY DRY RECENTLY, BUT PLEASE REMEMBER FLOOD SAFETY NEXT WEEK! IF
YOU ENCOUNTER FLOODED ROADS: TURN AROUND DON'T DROWN!
AS FOR TEMPERATURES, THESE WILL BE TEMPERED A BIT BY THE HIGHER RAIN
CHANCES (ESPECIALLY THURSDAY THROUGH SATURDAY), WITH HIGHS GENERALLY
IN THE UPPER 70S TO LOWER 80S EACH DAY AND LOWS IN THE LOWER TO MID
60S EACH NIGHT.
AVIATION
(18Z TAFS)
ISSUED AT 1221 PM CDT SUN MAY 17 2026
SOUTHERLY WINDS AROUND 10 KNOTS GUSTING TO AROUND 15 KNOTS ARE
EXPECTED THIS AFTERNOON AT BOTH TERMINALS. VFR CIGS ARE EXPECTED
AT KHSV AT TIMES THROUGH 22Z, BEFORE DISSIPATING. WE WILL HAVE TO
WATCH TO SEE IF ISOLATED -TSRA COULD COME CLOSE TO THE KHSV TERMINAL,
BUT THAT IS NOT EXPECTED AT THIS TIME. LESS CLOUD COVER IS EXPECTED
AT THE KMSL TERMINAL. WINDS WILL BECOME LIGHTER AROUND 5 KNOTS
EARLY THIS EVENING. WINDS SHOULD KEEP FOG AT BAY AT THE TERMINALS.
SOUTHERLY WINDS WILL PICK UP TO AROUND 10 KNOTS GUSTING UP TO 18
KNOTS AFTER 18/15Z.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...KTW
SHORT TERM....KTW
LONG TERM....KTW
AVIATION...KTW
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