383
FXUS64 KHUN 181750
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1250 PM CDT SAT APR 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1050 PM CDT FRI APR 17 2026
- THERE IS A HIGH (80-90%) CHANCE FOR SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING. A FEW STORMS COULD PRODUCE GUSTY
WINDS AND SMALL HAIL.
- A COOL/DRY AIRMASS WILL OVERSPREAD THE REGION SUNDAY AND SUNDAY
NIGHT. THIS WILL BE FOLLOWED BY A DRY CONDITIONS AND A GRADUAL
WARMING TREND MONDAY-THURSDAY.
- CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BEGIN TO INCREASE ON
FRIDAY.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1050 AM CDT SAT APR 18 2026
EARLIER CLOUD COVER AROUND DAYBREAK HAS THINNED AND BROKEN UP NEAR
AND EAST OF THE I-65 CORRIDOR. THIS IS ALLOWING FOR SOME HEATING
DUE TO INSOLATION AS WELL AS WARM AIR ADVECTION CURRENT. RAP13
SEEMS TO BE CATCHING ONTO THIS TREND WELL WITH 13Z RH FORECAST
PARAMETERS AT VARIOUS MANDATORY LEVELS.
FURTHER WEST, DEEPER CLOUD COVER IS MORE ENTRENCHED. DEWPOINT
DEPRESSIONS ARE LIKELY TOO LARGE FOR PRECIPITATION TO BE REACHING
THE GROUND, DESPITE SOME RAINFALL RETURNS ALOFT. HOWEVER, BETWEEN
NOW AND 1 PM, EXPECT SOME OF THIS COULD REACH THE GROUND AS
SURFACE DEWPOINTS INCREASE AHEAD OF THE FRONT. MID LEVEL LAPSE
RATES ARE VERY STEEP, BUT THE ELEVATED MIXED LAYER IS VERY WARM
FORMING A VERY ROBUST CAP SEEN IN 7 AM SOUNDING DATA FROM BOTH
NASHVILLE, TN AND BIRMINGHAM, AL. THIS WILL LIKELY BE THE IMPEDING
FACTOR FOR SEVERE THUNDERSTORM DEVELOPMENT, DESPITE AMPLE SHEAR
THAT IS IN PLACE AND THAT SHOULD CONTINUE TO INCREASE INTO THE
EVENING HOURS AHEAD OF THE APPROACHING COLD FRONT.
CURRENT SURFACE TEMPERATURES ARE IN THE 76 TO 78 DEGREE RANGE IN
MOST AREAS. THE EXCEPTION TO THIS IS IN FAR WESTERN PORTIONS OF NW
ALABAMA WHICH HAS EXPERIENCED THICKER AND MORE PERSISTENT CLOUD
COVER. SOME ADDITIONAL BREAKS IN CLOUD COVER COULD LINGER INTO
PORTIONS OF NW ALABAMA THROUGH THE MORNING HOURS, BEFORE STRONGER
FORCING AT 700 MB AND 500 MB PUSH INTO THAT AREA AHEAD OF THE
APPROACHING FRONTAL BOUNDARY. TEMPERATURES SHOULD BE WARMEST NEAR
AND EAST OF THE I-65 CORRIDOR, CLIMBING INTO THE 76 TO 85 DEGREE
RANGE IN SOME AREAS. OVERALL, LOWERED HIGHS A TAD THOUGH.
GIVEN THAT MODEL GUIDANCE IS HOLDING ONTO VERY STRONG MID LEVEL *
LAPSE RATES (7.5 TO 8.0 DEGREES/KM) THROUGH 4 OR 5 PM THIS
AFTERNOON, SOME STRONG THUNDERSTORMS COULD DEVELOP EARLY THIS
AFTERNOON AS THE STRONGER 700 MB AND 500 MB FORCING AHEAD OF THE
FRONT PUSHES INTO NW ALABAMA AND FURTHER EAST. WOULD EXPECT BEST
INSTABILITY TO BE NEAR AND EAST OF THE I-65 CORRIDOR THIS
AFTERNOON, GIVEN THE MORE PERSISTENT BREAKS IN CLOUD COVER
EXPECTED THERE TODAY. GUIDANCE DOES SHOW SOME SURFACE BASED AND
ELEVATED CAPE BETWEEN 300 AND 800 J/KG THIS AFTERNOON. DEWPOINTS
MAY INCREASE ENOUGH RIGHT AHEAD OF THE FRONT FOR CLOSE TO 1000
J/KG OF SBCAPE TO DEVELOP IN PORTIONS OF NW ALABAMA AND SLIGHTLY
FURTHER EAST. THE MAIN RESULTS OF THIS COMBINATION OF FACTORS
WOULD LIKELY BE SOME SCATTERED STRONG STORMS PRODUCING SMALL HAIL
AND GUSTY WINDS GIVEN EXPECTED MID-LEVEL LAPSE RATES, JUST ENOUGH
INSTABILITY, AND STRONG FORCING THROUGH ABOUT 5 PM.
AS WE MOVE INTO THE EARLY EVENING HOURS, THE MID LEVEL LAPSE
RATES BECOME MUCH LESS ROBUST AND THE WET-BULB ZERO HEIGHTS CLIMB
ABOVE 10,000 FEET. THIS WOULD LIKELY LESSEN THE SMALL HAIL RISK,
BUT INCREASING SHEAR WILL LIKELY KEEP A VERY LOW THREAT FOR SMALL
HAIL AND GUSTY WINDS TO 50 MPH OR SO IN THE CARDS INTO THE
EVENING HOURS.
WE NEED THE RAINFALL. PWATS INCREASE TO BETWEEN 1.5 AND 1.7
INCHES, LATE THIS AFTERNOON AND EVENING. GIVEN SOME STRONG/CONCENTRATED
700 MB FORCING IS SHOWN IN MOST GUIDANCE AND SOME MORE SCATTERED
AREAS OF STRONGER 500 MB FORCING SHOWN, WE SHOULD GET SOME SOLID
RAINFALL OUT OF THIS. HOPEFULLY WE GET A SOLID HALF OF AN INCH TO
AN INCH ACROSS THE AREA. THE STRENGTH OF THE 700 MB FORCING AND
THERMODYNAMIC PROFILE LOOK LIKE THAT IS A GOOD POSSIBILITY. THE
STRONGEST FORCING PUSHES SOUTHEAST INTO THE AREA AROUND 4 PM (NW
AL) AND EXITS THE AREA (NE AL) JUST AFTER MIDNIGHT. THIS WILL BE
THE MOST CONCENTRATED/PERSISTENT PERIOD OF RAINFALL AND
THUNDERSTORMS. AS NOTED EARLIER, THE OVERLAP OF BETTER MID-LAPSE
RATES, STRONG SHEAR, AND BETTER INSTABILITY SHOULD BE IN THE
EARLY/MID AFTERNOON PERIOD. THIS WOULD BE THE PERIOD OF MORE
LIKELY STRONGEST THUNDERSTORM ACTIVITY.
SHORT TERM
(SUNDAY THROUGH TUESDAY)
ISSUED AT 1050 AM CDT SAT APR 18 2026
THIS FRONT AS NOTED IN EARLIER SECTION IS A QUICK MOVING BOUNDARY.
THIS SHOULD USHER IN SOME MUCH DRIER AND COLDER AIR BEHIND IT
OVERNIGHT. THROUGH ADVECTION OF MUCH DRIER/COOLER AIR, TEMPERATURES
SHOULD DROP INTO THE 40 TO 45 DEGREE RANGE BY DAYBREAK ON SUNDAY.
WITH THE COOL START ON SUNDAY, HIGHS WILL BE AT LEAST 5 TO 10
DEGREES BELOW NORMAL (MAYBE A BIT MORE IN HIGHER ELEVATIONS), ONLY
CLIMBING INTO THE 60 TO 70 DEGREE RANGE IN MOST LOCATIONS.
A PRETTY CHILLY NIGHT IS IN STORE SUNDAY NIGHT, AS LIGHT WINDS
AND CLEAR SKIES SHOULD ALLOW LOWS TO DROP TO BETWEEN 39 AND 45
DEGREES (5 TO 10 DEGREE BELOW NORMAL).
AS WE MOVE INTO MONDAY AND MONDAY NIGHT, UPPER LEVEL RIDGING
BEGINS TO RE-ESTABLISH ITSELF OVER THE DESERT SOUTHWEST. OVER THE
TENNESSEE VALLEY AREA, NORTHWEST FLOW ALOFT WILL STILL BE IN
PLACE, BUT BEGIN TO MODIFY. THIS NORTHWEST FLOW ALOFT WILL KEEP
HIGHS NEAR OR SLIGHT BELOW NORMAL. HIGHS ON MONDAY LOOK TO CLIMB
BACK INTO THE UPPER 60S TO AROUND 75 DEGREES. LOWS SHOULD WARM
A BIT INTO THE MID TO UPPER 40S BY TUESDAY MORNING. DURING THE DAY
ON TUESDAY, HIGHS SHOULD REBOUND BACK INTO THE MID 70S TO LOWER
80S (NEAR OR ABOVE NORMAL VALUES).
LONG TERM
(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 1050 AM CDT SAT APR 18 2026
DURING THIS PERIOD THE UPPER RIDGE WILL SHIFT EAST AND OVER THE
TENNESSEE VALLEY. UNFORTUNATELY, VERY DRY WEATHER IS EXPECTED
SUNDAY THOUGH THE BEGINNING OF NEXT WEEK AT LEAST, LIKELY THROUGH
THE END OF THE WEEK. HIGHS WILL CONTINUE TO WARM UP INTO THE 80S
AS THE UPPER RIDGE BUILDS MORE OVER THE AREA TOWARDS THE
MIDDLE/END OF NEXT WEEK. LOWS SHOULD WARM INTO THE 50S AND LOWER
60S.
NEXT WEEKEND LOOKS A BIT MORE UNSETTLED WITH THE POSSIBILITY OF
MUCH MORE NEEDED RAINFALL, BUT MAYBE SOME MORE ROBUST THUNDERSTORM
ACTIVITY.
AVIATION
(18Z TAFS)
ISSUED AT 1250 PM CDT SAT APR 18 2026
VFR CONDITIONS ARE EXPECTED TO CONTINUE TO BE PREDOMINANT AT THE
KMSL TERMINAL THROUGH 20Z. HOWEVER, A PROB30 FOR -RA AND MVFR
VSBYS WAS INCLUDED FROM 19Z TO 20Z. EXPECT PREDOMINANT MVFR CIGS
OR VSBYS TO OCCUR AFTER 20Z AT KMSL WITH SHRA. A TEMPO GROUP
BETWEEN 21Z AND 01Z WAS INCLUDED FOR TSRA. WILL HAVE TO WATCH FOR
POSSIBLE INCLUSION OF IFR CONDITIONS ONCE CONVECTION BEGINS
DEVELOPING. EXPECT MVFR CIGS AND -SHRA TO HANG AROUND EARLY THIS
EVENING AT KMSL, BEFORE VFR CONDITIONS RETURN AT KMSL AROUND 4Z.
FURTHER EAST, VFR CONDITIONS SHOULD HOLD ON LONGER AND INCLUDED A
LONGER PROB30 WINDOW FOR -SHRA AND MVFR CIGS (19Z TO 21Z). EXPECT
PREDOMINANT SHRA AND MVFR CIGS TO DEVELOP THERE CLOSER TO 22Z WITH
A TEMPO GROUP FOR TSRA BETWEEN 23Z AND 03Z. AGAIN, IFR CONDITIONS
MAY NEED TO BE ADDED DEPENDING ON CONVECTIVE INTENSITY. EXPECT
MVFR CIGS AND -SHRA TO HANG AROUND EARLY THIS EVENING, BEFORE VFR
CONDITIONS RETURN AT KHSV AROUND 5Z.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...KTW
SHORT TERM....KTW
LONG TERM....KTW
AVIATION...KTW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page