413
FXUS64 KHUN 181702
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1202 PM CDT THU JUN 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 328 AM CDT THU JUN 18 2026
- MEDIUM TO HIGH CHANCES FOR RAIN AND THUNDERSTORMS TODAY AS THE
REMNANTS OF ARTHUR TRACK ALONG THE GULF COAST STATES. THERE IS
A SLIGHT RISK (LEVEL 2 OF 4) FOR EXCESSIVE RAINFALL/LOCALIZED
FLOODING AND A MARGINAL RISK (LEVEL 1 OF 5) FOR GUSTY TO
DAMAGING THUNDERSTORM WINDS.
- AFTER A BRIEF PERIOD OF DRY WEATHER LATE FRIDAY INTO SATURDAY
MORNING, ADDITIONAL ROUNDS OF RAIN AND THUNDERSTORMS ARE
FORECAST INTO THE LONG TERM PERIOD WITH HIGH RAIN CHANCES
SUNDAY AND MONDAY.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1039 AM CDT THU JUN 18 2026
SEVERAL LOCALIZED CONVERGENCE BOUNDARIES ARE SWEEPING THROUGH THE
TENNESSEE VALLEY THIS MORNING AS THE REMNANTS OF TROPICAL STORM
ARTHUR ENTER THE CENTRAL GULF COAST. AS THIS PROGRESSES INLAND,
THE MAIN FEATURE OF FOCUS WILL BE WHERE THE CENTER TRACKS. THE
TRACK WILL IMPACT LOCATION OF HIGHEST GRADIENT WINDS, AXES OF
HIGHER RAINFALL, AND STRONGER SHEAR CREATING MORE FAVORABLE
CONDITIONS FOR TROPICAL TORNADOES.
AT THIS TIME, MOST INDICATIONS ARE THAT THE CENTER SHOULD REMAIN
OVER CENTRAL ALABAMA AS IT TRACKS EAST INTO GEORGIA. THIS MOST
LIKELY SCENARIO WOULD RESULT IN WIDESPREAD RAINFALL TOTALS OF
0.5-1.5" FOR THE TN VALLEY WITH THE HIGHER CORRIDOR OF RAINFALL
REMAINING SOUTH. ADDITIONALLY, THE TORNADO THREAT SHOULD ALSO STAY
SOUTH OF OUR AREA. PRIMARY CONCERNS WILL BE THE TROPICAL AIR MASS
WITH PWATS OF 2"+ WITH MOIST ADIABATIC PROFILES UP THROUGH 700-MB
LEADING TO HEAVY RAINFALL RATES AND OCCASIONALLY GUSTY WINDS. MOST
LIKELY WIND GUSTS WILL BE UP TO 40-50 MPH WITH A VERY LOW RISK FOR
ANY SEVERE WINDS.
THROUGH THE REMAINDER OF THE DAY, WE WILL KEEP A CAUTIOUS EYE ON
THE LOW PROBABILITY HIGH-END SCENARIO, WHICH IS REPRESENTED BY THE
00Z MPAS RRFS EXPERIMENTAL GUIDANCE. THIS HAS THE REMNANTS
TRACKING MORE TO THE NORTHEAST AND CROSSING OVER THE TN VALLEY,
WHILE ALSO DEEPENING THE LOW, RESULTING IN INTENSIFICATION. IT IS
VERY UNLIKELY THAT THE LOW INTENSIFIES THIS FAR INLAND, SO WHILE
THIS IS LIKELY AN UNREPRESENTATIVE SOLUTION, IT DEMONSTRATES WHAT
THE HIGHER END IMPACTS WOULD BE FOR THE TN VALLEY. HEAVY RAINFALL
AXES OF 3-5" AND STRONGER SHEAR FAVORABLE FOR TORNADOES AND
DAMAGING WIND GUSTS UP TO 60 MPH. IT IS WORTH RESTATING THAT THE
MPAS IS NEWER, EXPERIMENTAL GUIDANCE AND THIS IS THE FIRST
TROPICAL SYSTEM I HAVE OBSERVED WITH THIS MODEL.
AFTER ROUGHLY 00Z, THE CENTER OF THE LOW WILL PROGRESS OUT OF THE
REGION. INCREASED SUBSIDENCE WILL LESSEN THE EXTENT OF ANY
PRECIPITATION ASSOCIATED WITH A SLOW-MOVING BOUNDARY THAT WILL
PUSH SOUTHWARD FROM TENNESSEE HEADING INTO THE OVERNIGHT PERIOD.
LOOK FOR HIGHS TODAY TO PEAK IN THE LOW TO MID 80S WITH OVERNIGHT
LOWS DROPPING INTO THE UPPER 60S UNDERNEATH MOSTLY CLOUDY SKIES.
SHORT TERM
(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 1039 AM CDT THU JUN 18 2026
THE COLD FRONT WILL CONTINUE TO SAG SOUTHWARD TOMORROW THROUGH THE
REGION. OVERALL RAIN CHANCES ARE LOW (10-20%) OVER THE TN VALLEY
WITH THIS FRONT, BUT INCREASE SOUTH OF THE AREA WHERE THE FRONT IS
EXPECTED TO STALL. SHOULD THE FRONT STRUGGLE TO PUSH SOUTH OF US,
A MORE LIKELY CASE SHOULD ARTHUR'S REMNANTS TRACK FARTHER NORTH,
THEN FRIDAY'S RAIN CHANCES WILL DRASTICALLY INCREASE. FRIDAY NIGHT
LOOKS TO BE MORE PLEASANT AS SURFACE HIGH PRESSURE SLIDES ACROSS
NORTH OF THE STALLED BOUNDARY, BRINGING MOSTLY CLEAR SKIES AND
OVERNIGHT LOWS IN THE MID 60S. THE BOUNDARY IS PICKED UP BY A LEE
CYCLONE OVER THE ROCKIES AND WILL PUSH NORTHWARD ON SATURDAY.
THIS WILL BRING 30-40% RAIN CHANCES TO SOUTHERN AND WESTERN AL
SATURDAY MORNING AND AFTERNOON DUE TO DIURNAL ENHANCEMENT.
LONG TERM
(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 1006 PM CDT WED JUN 17 2026
ZONAL FLOW WILL LARGELY PERSIST THROUGH MUCH OF THE LONG TERM
PERIOD, WITH SEVERAL RIPPLES OF SHORTWAVES MOVING ALONG THE FLOW
DURING THIS TIME. HOWEVER, THE PATTERN LOOKS TO CHANGE A BIT BY
MIDWEEK, WITH NORTHWEST FLOW TAKING HOLD. AT THE SURFACE, A REMNANT
BOUNDARY WILL EITHER DISSIPATE OR MOVE NORTH OF THE REGION ON SUNDAY.
ANOTHER COLD FRONT IS THEN SHOWN TO APPROACH THE SOUTHEAST ON
MONDAY, WITH FROPA THROUGH NORTH ALABAMA AND SOUTHERN MIDDLE
TENNESSEE SOMETIME BETWEEN MONDAY NIGHT AND TUESDAY. HIGH PRESSURE
THEN BUILDS DOWN INTO THE TENNESSEE VALLEY QUICKLY BEHIND THE FRONT
FOR MIDWEEK.
OVERALL, EXPECT DAILY CHANCES OF SHOWERS AND STORMS, BUT WITH HIGHER
CHANCES SUNDAY AND MONDAY (40-80%) AND LOWER CHANCES TUESDAY AND
WEDNESDAY (20-40%). WHILE THUNDERSTORM DEVELOPMENT IS SUPPORTED DUE
TO SUFFICIENT INSTABILITY AND BULK SHEAR, GUIDANCE SUGGESTS MIDLEVEL
LAPSE RATES MAINLY BETWEEN 5-6.5 DEGC/KM. THEREFORE, CONFIDENCE IS
LOW IN ANY STRONG TO SEVERE STORM POTENTIAL AT THIS POINT. HOWEVER,
WITH PWATS BETWEEN 1.7-2.1 INCHES SUNDAY AND MONDAY, THESE STORMS
WILL BE EFFICIENT RAINFALL PRODUCERS AND BRING THE THREAT OF HEAVY
RAINFALL AND AT LEAST MINOR FLOODING (ESPECIALLY WITH SATURATED
ANTECEDENT CONDITIONS). MOISTURE GRADUALLY DECREASES FROM TUESDAY
INTO WEDNESDAY, WITH A MORE SUMMERTIME-LIKE PATTERN THEN SETTING UP
(DIURNAL SHOWERS/STORMS).
AS FOR TEMPERATURES, HIGHS WILL GENERALLY REMAIN IN THE MID TO UPPER
80S SUNDAY THROUGH WEDNESDAY. BUT, LOWS WILL GRADUALLY DECREASE FROM
THE LOWER 70S SUNDAY NIGHT TO THE MID TO UPPER 60S BY TUESDAY NIGHT
THANKS TO FROPA AND DECREASING MOISTURE.
AVIATION
(18Z TAFS)
ISSUED AT 1202 PM CDT THU JUN 18 2026
MVFR TO IFR CEILINGS WILL FLUCTUATE AT BOTH TERMINALS AS PERIODS
OF HEAVY RAIN AND THUNDER CONTINUE TO PUSH THROUGH NORTH ALABAMA.
HEAVIEST SHOWERS ARE FORECAST THIS AFTERNOON WITH POTENTIAL
AIRPORT IMPACTS CAPTURED IN THE TEMPO GROUP FROM 18-22Z. HEAVIEST
SHOWERS/STORMS WILL LIKELY DROP CEILINGS AND VISIBILITIES BRIEFLY
AS THEY MOVE THROUGH. THERE WILL ALSO BE A MEDIUM CHANCE OF
LIGHTNING AND WINDS GUSTS OF 25+ MPH AMONG STRONGEST STORMS. AS WE
GET CLOSER TO 00Z, RAIN AND THUNDER WILL BEGIN TO END FROM WEST
TO EAST, WITH DRY CONDITIONS IN PLACE BY 06Z. UNFORTUNATELY, MVFR
TO IFR CEILINGS LOOK TO REMAIN THROUGH THE NIGHT AND INTO THE
MORNING TOMORROW.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...30
SHORT TERM....30
LONG TERM....26
AVIATION...RAD
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