497
FXUS64 KHUN 181110
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
610 AM CDT FRI APR 18 2025
..NEW AVIATION
NEAR TERM
(TODAY)
ISSUED AT 400 AM CDT FRI APR 18 2025
CALM WINDS HAVE HELD ON IN FAR NORTHEASTERN ALABAMA AND IN
PORTIONS OF FRANKLIN COUNTY (TN). FURTHER WEST, WINDS HAVE
REMAINED BETWEEN 5 AND 10 MPH MOSTLY. THESE STRONGER WINDS HAVE
HELPED KEEP TEMPERATURES MUCH WARMER WEST OF THE I-65 CORRIDOR
(LOWER TO MID 60S). FURTHER EAST TEMPERATURES HAVE DROPPED INTO
THE LOWER 50S TO AROUND 60 DEGREES. SOME LOCATIONS (ESPECIALLY IN
SHELTERED VALLEY LOCATIONS) IN NE ALABAMA COULD SEE LOWS IN THE
UPPER 40S WHEN YOU WAKE UP THIS MORNING. FURTHER WEST, LOWS WILL
LIKELY BE IN THE UPPER 50S TO LOWER 60S.
MOST GUIDANCE CONTINUES TO SHOW VERY WARM CONDITIONS FOR TODAY.
925 MB TEMPERATURES IN MOST GUIDANCE CLIMB TO BETWEEN 20 AND 23
DEGREES CELSIUS IN THE AFTERNOON. SOME THIN BUT HIGH CLOUD COVER
WILL MOVE ACROSS THE AREA MAINLY THIS MORNING. HOWEVER, THE THIN
AND HIGH NATURE OF THIS CLOUD COVER DOESN'T LOOK TO HINDER
INSOLATION THAT MUCH AND MOST GUIDANCE BREAKS THIS UP IN THE
AFTERNOON. MODELS HAVE TRENDED 2 TO 3 DEGREES TOO COOL THE LAST
FEW DAYS. GIVEN THE 925 MB TEMPERATURE FORECAST AND STRONG
INSOLATION EXPECTED, BUMPED UP HIGHS FROM THE STRAIGHT NBM A FEW
DEGREES INTO THE 82 TO 88 DEGREE RANGE IN MOST LOCATIONS (WARMEST
WEST OF I-65 CORRIDOR).
MODELS CONTINUE TO SHOW THE POTENTIAL FOR MIXING SOME DRIER AIR
TO THE SURFACE THIS AFTERNOON. LOW LEVEL MOISTURE ADVECTION WILL
LIKELY COUNTERACT THAT NEAR AND WEST OF I-65. HOWEVER, NOT SO SURE
IT WILL FURTHER EAST UNTIL VERY LATE IN THE AFTERNOON. THUS, HAVE
LOWERED THE AFTERNOON DEWPOINT FORECAST INTO THE UPPER 30S TO
LOWER 40S TODAY IN NE ALABAMA. THIS WILL DROP RELATIVE HUMIDITY
VALUES INTO THE 22 TO 28 PERCENT RANGE IN PORTIONS OF NORTHEASTERN
ALABAMA. IT WILL BE BREEZY TOO WITH SUSTAINED WINDS OF 10 TO 15
MPH WITH GUSTS UP TO 30 MPH POSSIBLE. LUCKILY, KBDI VALUES ARE
LESS THAN 300, KEEPING RED FLAG CONDITIONS AT BAY. HOWEVER, TODAY
WOULD NOT BE A GOOD DAY TO DO ANY OUTDOOR BURNING GIVEN THE VERY
DRY CONDITIONS AND WINDS EXPECTED IN NE ALABAMA.
SHORT TERM
(TONIGHT THROUGH SUNDAY)
ISSUED AT 930 PM CDT THU APR 17 2025
DRY WEATHER CONDITIONS ARE LIKELY FOR FRIDAY NIGHT THROUGH SUNDAY
AS THE MID/UPR SUB-TROPICAL RIDGE TENDS TO MIGRATE TO THE SW,
MAINTAINING A PRESENCE LARGELY IN THE VICINITY OF THE FL PENINSULA
DURING THE PERIOD. WITH THE UPR RIDGE HOLDING SWAY ACROSS OUR
AREA, THE PRIMARY RIDGE/TROUGH INTERFACE AND AXIS FOR STORMY
WEATHER WILL LIE GENERALLY TO OUR WEST, FROM THE SOUTHERN PLAINS
INTO THE MIDWEST. TEMPERATURES WILL RISE INTO THE 80S EACH DAY
DURING THE PERIOD, DESPITE PERIODS OF CIRRUS (PERHAPS OPAQUE AT
TIMES) MOVING ACROSS THE REGION. SATURDAY MAY BE THE OVERALL
WARMEST DAY WITH A PLUME OF ~16-18C TEMPS UP TO MIXING HEIGHT
(~850 MB) MOVE ACROSS THE REGION. OVERNIGHT LOWS WILL BE MILD WITH
INCREASING DEW POINTS AND LIGHT WINDS MAINTAINING LOW-LVL MIXING
OVERNIGHT.
LONG TERM
(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 930 PM CDT THU APR 17 2025
THE LONG WAVE PATTERN WILL BEGIN TO CHANGE GRADUALLY BEGINNING
LATE SUNDAY INTO MONDAY. THE BROAD MID/UPR RIDGE WILL GRADUALLY
FLATTEN OVER THE PERIOD, BUT THE TENDENCY FOR LONG WAVE RIDGING
WILL REMAIN IN THE EAST CONUS VS THE WEST. AN INITIAL SHORT WAVE
TROUGH WILL RIDGE ALONG THE TROUGH/RIDGE INTERFACE TO OUR WEST
STARTING SUNDAY NIGHT AND CONTINUING INTO MONDAY. AN ATTENDANT SFC
LOW WILL MOVE NORTHEASTWARD INTO THE MIDWEST, DRAGGING A COLD
FRONT EVENTUALLY ACROSS THE TN VALLEY. DYNAMIC FORCING WILL TEND
TO WEAKEN AS THE FRONT CROSSES THE AREA, WITH OVERALL LIFT AND
RESULTING RAINFALL INTENSITY/COVERAGE LIKEWISE WEAKENING.
NEVERTHELESS, RAINFALL AMOUNTS AROUND 0.5 TO 1.0 INCH COULD OCCUR
ACROSS THE AREA, BEGINNING LATE SUNDAY NIGHT IN THE WEST AND
LASTING INTO MONDAY. THE HIGHER AMOUNTS WILL LIKELY BE IN THE WEST
CLOSER TO THE BETTER FORCING. INSTABILITY AND STRONG DEEP LAYER
SHEAR WILL BE LACKING WITH THIS EVENT, SO CHANCES FOR ANY SEVERE
WEATHER APPEAR TO BE SMALL AT THIS TIME.
THE FRONT IS EXPECTED TO CLEAR THE AREA LATE MONDAY, BUT THERE IS
SOME QUESTION IN THE ENSEMBLES AS TO THE PROGRESSION OF THE FRONT,
LEADING TO SOME UNCERTAINTY IN THIS PERIOD. HOWEVER, THE GREATER
PORTION OF THE MODEL EVIDENCE SUGGESTS DRYING OUT ON TUESDAY
GRADUALLY, ALTHOUGH THE SYNOPTIC BOUNDARY MAY LINGER IN THE
REGION. ANOTHER RELATIVELY WEAK, BUT QUICKLY TRANSITING UPR WAVES
MAY BRING OTHER ROUNDS OF SHOWERS/STORMS ON WEDNESDAY AND
THURSDAY, BUT DUE TO THE FEATURES INVOLVED AND THE UNCERTAINTY IN
THE LOCATION OF THE BROAD SCALE BOUNDARY, POPS WILL BE RELATIVELY
LOW AT THIS TIME.
AVIATION
(12Z TAFS)
ISSUED AT 606 AM CDT FRI APR 18 2025
SOUTHERLY WINDS BETWEEN 10 AND 15 KNOTS WITH SOME GUSTS AROUND 25
KNOTS ARE EXPECTED TODAY. HIGH CLOUDS THROUGH 16Z SHOULD BREAK UP
TOWARDS NOON AND INTO THE AFTERNOON HOURS. WINDS SHOULD LESSEN TO
BETWEEN 5 AND 10 KNOTS AFTER 00Z.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...KTW
SHORT TERM....KDW
LONG TERM....KDW
AVIATION...KTW
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