827
FXUS64 KMRX 081107
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
707 AM EDT THU MAY 8 2025
..NEW AVIATION
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 313 AM EDT THU MAY 8 2025
KEY MESSAGES:
1. STORMS WILL MOVE THROUGH THE REGION LATE THIS AFTERNOON INTO THE
EVENING HOURS.
2. SOME STORMS WILL LIKELY BE STRONG TO SEVERE WITH LARGE HAIL AS
THE GREATEST CONCERN, UP TO THE SIZE OF GOLF BALLS. LOCALIZED
DAMAGING WINDS ARE ALSO POSSIBLE.
DISCUSSION:
CURRENTLY EARLY THIS MORNING, A WEAKENING CLOSED LOW IS CENTERED
OVER MISSOURI WITH A FRONTAL BOUNDARY JUST SOUTH OF OUR REGION. A
WEAK AREA OF LOW PRESSURE IS ALSO CENTERED JUST SOUTHEAST OF THE
UPPER LOW. THROUGHOUT THE DAY, THE UPPER LOW WILL LIFT TOWARDS THE
OHIO RIVER VALLEY WITH THE WEAK SURFACE LOW FOLLOWING A SIMILAR
TREND. THIS WILL ALSO ALLOW PULL THE FRONTAL BOUNDARY NORTHWARD INTO
OUR AREA AS A WARM FRONT. THE COMBINATION OF SURFACE HEATING AND
HEIGHT FALLS WILL ENHANCE THE THERMODYNAMIC ENVIRONMENT. THIS IS
ESPECIALLY TRUE WITH INDICATIONS OF MLCAPE TO 1,500 J/KG OR MORE AND
MID-LEVEL LAPSE RATES AROUND 7 CELSIUS/KM. THE CAMS INDICATE
DEVELOPMENT BEING GENERALLY TO OUR NORTHWEST DURING THE AFTERNOON
WITH A PROGRESSION THROUGH OUR AREA AROUND 4 TO 9 PM. THIS TIMING
WILL ALLOW FOR FURTHER DESTABILIZATION.
WINDS WILL BE FAIRLY UNI-DIRECTIONAL THROUGH THE PROFILE AND WEAKER
IN THE LOWER LEVELS, BUT EFFECTIVE SHEAR OF 30 KTS OR GREATER IS
ALSO ANTICIPATED. THIS ENVIRONMENT WILL SUPPORT ORGANIZED CONVECTION
WITH SOME SUPERCELLS ALSO POSSIBLE. ON TOP OF THE OVERALL LAPSE
RATES AND INSTABILITY, WBZ HEIGHTS WILL BE BELOW 10,000 FEET AGL
WITH INDICATIONS THAT 50 DBZ RETURNS AT JUST 25,000 FEET AGL BEING
SUFFICIENT FOR 1 INCH HAIL. HAIL CAPE (-10 TO -30 CELSIUS REGION) IS
ALSO INDICATED TO SURPASS 600 J/KG. THIS REALLY UNDERSCORES THE HAIL
THREAT WITH GOLF BALL-SIZED REPORTS POSSIBLE. THE ORGANIZED NATURE
OF STORMS WILL ALSO SUPPORT A DAMAGING WIND THREAT AS WELL. WITH HOW
WEAK THE FLOW IS IN THE LOWER LEVELS, THE TORNADO THREAT IS LOW
OVERALL UNLESS SOMETHING WERE TO SPIN UP ALONG THE BOUNDARY ITSELF.
ACTIVITY IS EXPECTED TO DIMINISH ALONG SOUTHERN PORTIONS OF THE AREA
LATER IN THE NIGHT AS THE FRONT DRIFTS BACK SOUTHWARD. MORNING FOG
WILL BE POSSIBLE FOLLOWING THE RECENT RAINFALL.
LONG TERM
(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 313 AM EDT THU MAY 8 2025
KEY MESSAGES:
1. FOR FRIDAY THROUGH SUNDAY, RAIN CHANCES WILL BE VERY LIMITED
OUTSIDE OF THE SOUTHERN HALF OF THE AREA.
2. BY NEXT WEEK, MORE WIDESPREAD RAINFALL IS LIKELY WITH STORMS
POSSIBLE TUESDAY AND WEDNESDAY.
FRIDAY THROUGH SUNDAY
AT THE START OF THE PERIOD, A CLOSED LOW WILL BE CENTERED OVER THE
EASTERN GREAT LAKES WITH ANOTHER CLOSED LOW DEVELOPING OVER
ARKANSAS. THE FRONTAL BOUNDARY FROM THE SHORT TERM PERIOD WILL BE
CENTERED JUST TO OUR SOUTH. THROUGHOUT THE DAY ON FRIDAY, THE CLOSED
LOW TO OUR SOUTHWEST WILL STRENGTHEN WITH THE FRONTAL BOUNDARY
DRIFTING FURTHER SOUTH AS HIGH PRESSURE EXPANDS FROM THE NORTH. THIS
WILL KEEP TEMPERATURES FAIRLY MILD WITH RAIN CHANCES FOCUSED IN
SOUTHERN PORTIONS OF THE AREA. BY SATURDAY, THE NORTHEASTERN CLOSED
LOW WILL BE TRACKING INTO NEW ENGLAND WITH THE SOUTHWESTERN ONE
DRIFTING TOWARDS THE NORTHWESTERN GULF. FURTHER EXPANSION OF HIGH
PRESSURE WILL SHIFT RAIN CHANCES EVEN MORE SOUTHWARD WITH MUCH OF
THE AREA LIKELY REMAINING DRY. BY SUNDAY, THE NORTHEASTERN CLOSED
LOW WILL HAVE LIFTED AWAY FROM THE U.S. WITH THE ONE TO OUR
SOUTHWEST EXPECTED TO DEEPEN. FOR SUNDAY ITSELF, CONTINUED HIGH
PRESSURE WILL KEEP MUCH OF THE NORTHERN HALF OF THE AREA DRY.
MONDAY THROUGH WEDNESDAY
BY EARLY NEXT WEEK, THE CLOSED LOW IS CURRENTLY FORECAST TO TRACK
NORTHWARD ALONG THE MISSISSIPPI RIVER VALLEY, WHICH WILL BRING A
RETURN OF MORE WIDESPREAD RAINFALL TO THE AREA. BY TUESDAY, WAA FROM
ITS PROGRESSION WILL LIKELY BRING INSTABILITY SUFFICIENT FOR
SCATTERED CONVECTION. BY WEDNESDAY, THIS CLOSED LOW WILL LIFT TO THE
NORTH WITH A DEEP TROUGH TO OUR NORTHWEST COMING INTO VIEW. THIS MAY
PROVIDE EVEN BETTER SUPPORT FOR ORGANIZED CONVECTION ACROSS A LARGE
AREA. CURRENTLY, ANALOGS ARE SHOWING AT LEAST LOW-END CHANCES FOR
STRONG TO SEVERE STORMS TUESDAY AND/OR WEDNESDAY, SO IT WILL BE
WORTH WATCHING.
AVIATION
(12Z TAFS)
ISSUED AT 704 AM EDT THU MAY 8 2025
FOG AND LOW CLOUDS HAS PRODUCED MVFR CONDITIONS AT ALL OF THE
TERMINALS THIS MORNING. THESE CONDITIONS SHOULD IMPROVE BY LATE
MORNING, GIVING WAY TO VFR AND A PERSISTENT SOUTHWESTERLY TO
WESTERLY WIND. BY LATE AFTERNOON INTO EARLY EVENING, STORMS ARE
EXPECTED TO MOVE INTO THE AREA FROM THE WEST. IT IS LIKELY THAT
ALL OF THE TAF SITES WILL SEE REDUCTIONS TO MVFR OR LOWER.
HOWEVER, THERE IS STILL A LOT OF UNCERTAINTY AS TO WHEN THIS WILL
OCCUR AT EACH OF THE TERMINALS. SOME SOURCES SUGGEST THIS
TIMEFRAME TO BE LATER IN THE EVENING. AT THIS TIME, THE PROB30S
WERE MAINTAINED, BUT ADDITIONAL CHANGES WILL BE CONSIDERED IN
FUTURE ISSUANCES.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 81 59 77 55 / 50 50 40 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 78 57 74 51 / 50 50 30 10
OAK RIDGE, TN 77 57 74 50 / 50 50 20 10
TRI CITIES AIRPORT, TN 76 55 70 45 / 60 60 40 10
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...BW
LONG TERM....BW
AVIATION...BW
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