132
FXUS64 KHUN 040059
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
759 PM CDT FRI JUL 3 2020
NEAR TERM
(TONIGHT)
ISSUED AT 758 PM CDT FRI JUL 3 2020
SHOWERS AND AN ISOLATED THUNDERSTORMS DEVELOPED THIS AFTERNOON MAINLY
DUE TO DIURNAL HEATING, BUT ADDITIONAL DEVELOPMENT FORMED ALONG A
WEAK CONVERGENCE BOUNDARY OVER IN THE CUMBERLAND PLATEAU AND A WEAK
BOUNDARY JUST ACROSS THE AL/MS LINE. ACTIVITY IS EXPECTED TO DIMINISH
WITH SUNSET AND CLOUD COVER WILL START TO DECREASE LEAVING SKIES
MOSTLY CLEAR TONIGHT. COMBINED WITH THE LIGHT WINDS AND MOISTURE IN
PLACE, PATCHY FOG IS POSSIBLE AGAIN TONIGHT/EARLY TOMORROW MORNING.
OTHERWISE, TONIGHT WILL FEEL MUCH LIKE LAST NIGHT, HUMID WITH LOWS IN
THE UPPER 60S TO LOWER 70S. AS FOR THE GRIDS, EXTENDED POPS FOR
ANOTHER HOUR AND ADJUSTED CLOUD COVER TO ACCOMMODATE CURRENT TRENDS,
BUT NO MAJOR CHANGES WERE MADE.
SHORT TERM
(SATURDAY THROUGH SUNDAY)
ISSUED AT 255 PM CDT FRI JUL 3 2020
AN AREA OF HIGH PRESSURE JUST TO OUR NORTH WILL CONTINUE TO PROMOTE
HOT AND HUMID WEATHER FOR INDEPENDENCE DAY (SATURDAY) AS WE WILL
ONCE AGAIN SEE HIGHS IN THE LOWER 90S WITH HEAT INDEX VALUES CLOSE TO
THE 100 DEGREE MARK ONCE AGAIN. DO EXPECT SOME SLIGHTLY BETTER
PROSPECTS FOR DIURNAL CONVECTION IN THE AFTERNOON/EARLY EVENING
(MAINLY SOUTH OF THE TENNESSEE RIVER), AS A WEAK AREA OF LOW PRESSURE
ALONG THE GULF COAST AND ITS ASSOCIATED CONVERGENCE BOUNDARY SLOWLY
NUDGES ITS WAY NORTH. THE BEST FORCING WILL REMAIN WELL TO OUR SOUTH,
HOWEVER, SO THINK THIS WILL SCATTERED IN NATURE AT BEST AND TIED TO
THE PEAK HEATING OF THE DAY.
THE AFOREMENTIONED AREA OF LOW PRESSURE AND ASSOCIATED BOUNDARIES
WILL LIFT CLOSER TO THE I-20 CORRIDOR ON SUNDAY. WITH DEEPER MOISTURE
AND LOWER CONVECTIVE TEMPERATURES, THINK SCATTERED TO NUMEROUS
SHOWERS AND STORMS WILL BE MORE COMMON ON SUNDAY. CLOUD COVER WILL
LIKELY KEEP HIGH TEMPERATURES 2-3 DEGREES LOWER, BUT IT WILL LIKELY
FEEL WORSE JUST DUE TO THE TROPICAL-LIKE AIR MASS IN PLACE WITH PWATS
IN EXCESS OF 2". FOR THIS REASON, EXPECT HEAVY RAINFALL AND
POTENTIALLY SOME VERY LOCALIZED FLOODING CONCERNS TO START TO BE AN
ISSUE SUNDAY AFTERNOON INTO SUNDAY NIGHT.
LONG TERM
(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 255 PM CDT FRI JUL 3 2020
A "CUT OFF" LOW WILL CONTINUE TO MEANDER NORTH INTO THE TENNESSEE
VALLEY AND SOUTHERN APPALACHIAN REGION, BRINGING GOOD CHANCES FOR
WIDESPREAD SHOWERS AND THUNDERSTORMS EACH DAY THROUGH AT LEAST THE
MIDDLE OF THE WEEK. THIS ACTIVITY WILL LIKELY NOT BE SEVERE OR
EVEN STRONG IN NATURE. HOWEVER, DUE TO THE TROPICAL AIR MASS (PWATS
UP TO 2.3") IN PLACE, A SETUP FOR HEAVY RAINFALL AND AT LEAST
LOCALIZED FLASH FLOODING MAY DEVELOP. EVEN BY JULY STANDARDS THIS
WILL BE A MOIST ENVIRONMENT, WITH THE AFOREMENTIONED PWATS IN THE
90-95TH PERCENTILE FOR THIS TIME OF YEAR, PER THE KBMX SOUNDING
CLIMO. GIVEN THE TRACK OF THIS FEATURE, EXPECT S/SE FLOW TO CONTINUE
TO ADVECT WARM, MOIST AIR FROM THE GULF INTO THE AREA ON MONDAY, WITH
SOME WEAK LOW-LEVEL CONVERGENCE AXES THAT WILL ROTATE AROUND THE LOW,
HELPING TO FOCUS THIS AND INITIATE WIDESPREAD CONVECTION CAPABLE OF
PRODUCING HEAVY DOWNPOURS DURING THE DAYTIME PERIODS. DUE TO THE
SLOW-MOVING NATURE OF THIS SYSTEM, THE NBM HAS ALREADY PLACED US IN
CATEGORICAL POPS MONDAY THROUGH WEDNESDAY AS THERE IS FAIRLY HIGH
CONFIDENCE OF THIS BEING A WET PERIOD FOR US. GIVEN THE CONVECTIVE
NATURE OF THIS ACTIVITY, IT WILL BE HARD TO PINPOINT QPF THIS FAR
OUT, BUT THINK THAT AT LEAST 1-2" OF RAINFALL SEEMS REASONABLE
DURING A MONDAY TO THURSDAY PERIOD, WITH LOCALLY HIGHER AMOUNTS. THE
LOW WILL GRADUALLY WEAKEN AS IT SHIFTS NE INTO THE APPALACHIANS AND
MID- ATLANTIC FINALLY, BY THURSDAY. AS A RESULT, WE SEE A DECREASE IN
POPS LATE THIS WEEK AS WELL AS A GRADUAL WARMING TREND BY TO NORMAL
TEMPERATURES (90/70) FOR EARLY TO MID JULY.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 635 PM CDT FRI JUL 3 2020
A FEW SHOWERS WILL BRUSH KMSL DUE TO A BOUNDARY JUST OFF TO THE
WEST, HOWEVER THIS ACTIVITY WILL DIMINISH WITH SUNSET. WITH LIGHT
WINDS AND MOSTLY CLEAR SKIES TONIGHT, FOG DEVELOPMENT IS POSSIBLE
EARLY SATURDAY MORNING REDUCING VIS TO MVFR. KEPT FOG IN AT KHSV AND
ADDED FOG IN AT KMSL FOR THIS TAF ISSUANCE DUE TO THE SHOWER
ACTIVITY NEAR THE TERMINAL THIS AFTERNOON. DIURNAL SHOWERS AND
THUNDERSTORMS ARE EXPECTED ONCE AGAIN SATURDAY AFTERNOON SO INCLUDED
A PROB30 STARTING AT 19Z.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...JMS
SHORT TERM...AMP.24
LONG TERM...AMP.24
AVIATION...JMS
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