634
FXUS64 KMRX 141158
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
758 AM EDT MON APR 14 2025
..NEW AVIATION
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 256 AM EDT MON APR 14 2025
KEY MESSAGES:
1. VERY WARM WITH BREEZY CONDITIONS TODAY.
2. A COLD FRONT EXPECTED TO IMPACT THE REGION TONIGHT MAY BRING
STRONG TO SEVERE STORMS PRIMARILY TO SOUTHWEST VA AND FAR
NORTHEASTERN REACHES OF TN. DAMAGING WINDS AND HAIL THE PRIMARY
THREATS.
DISCUSSION:
INCREASING WINDS FOR PARTS OF THE AREA THIS MORNING IS HELPING
KEEP OVERNIGHT TEMPERATURES ON THE WARMER SIDE. THE LOWS MAY NOT
REACH WHAT WAS INITIALLY FORECAST, SO THE IMMEDIATE FORECAST WAS
CHANGED TO CAPTURE THE TRENDS.
A LOW LEVEL JET IS CURRENTLY INCREASING AT THIS TIME, WITH NEAR
50KT FLOW EXPECTED THROUGH THE EARLY MORNING. THE WESTERLY
DIRECTION IS UNFAVORABLE FOR ANY MOUNTAIN WAVE ENHANCEMENT OF THE
SOUTHERN APPALACHIANS. WESTERLY TO EVENTUALLY SOUTHWESTERLY FLOW
WILL SET UP ACROSS THE REGION TODAY AHEAD OF A COLD FRONT PASSAGE
EXPECTED TONIGHT. IN RESPONSE, WINDS WILL INCREASE FOR THE LATER
MORNING AND AFTERNOON WITH GUSTS RANGING BETWEEN 25 AND 35 MPH
AREA-WIDE. HIGHER GUSTS POSSIBLE ACROSS THE HIGHER TERRAIN, BUT
FOR THE MOST PART SHOULD REMAIN BELOW WIND ADVISORY CRITERIA. VERY
WARM TEMPERATURES CAN ALSO BE EXPECTED TODAY WITH UPPER 70S TO
LOW 80S.
SURFACE HIGH PRESSURE CENTERED OVER FLORIDA AND SHORTWAVE RIDGING
WILL TRANSITION TO A TROUGH EVENTUALLY SKIRTING THE NORTHERN TIER
OF THE COUNTRY WITH A NEARLY STACKED SURFACE LOW CURRENTLY OVER
THE WESTERN GREAT LAKES. THE LOW IS FORECAST TO DEEPEN AS IT
SLOWLY PUSHES INTO CANADA AND EVENTUALLY EAST.
A COLD FRONT EXTENDING FROM THIS SYSTEM WILL REACH OUR AREA BY
TONIGHT. NORTHERN PARTS OF OUR FORECAST AREA ARE UNDER EITHER MRGL
TO SLGT RISK OF SEVERE WEATHER ACCORDING TO THE SPC. LOOKING AT
SIMU-REFLECTIVITY FROM A COUPLE OF CAMS, THE STRONGER STORMS
APPEAR WILL REMAIN NORTH INTO WEST VIRGINIA MOVING EAST INTO
VIRGINIA WHERE THE BETTER DYNAMICS ARE. ACCORDING TO THE HREF,
MUCAPE OF OVER 1000 J/KG CLIPS OUR SOUTHWEST VIRGINIA COUNTIES.
AMPLE LOW LEVEL AND DEEP LAYER SHEAR WILL SUPPORT THE FORMATION
AND LONGEVITY OF STORMS INTO THE OVERNIGHT HOURS WITH THE THREAT
DROPPING OFF TO THE SOUTH WITH LESSER INSTABILITY. UNIDIRECTIONAL
SPEED SHEAR OR STRAIGHT HODOS SUGGEST THE TORNADO THREAT BEING THE
LESS LIKELY ELEMENT. DAMAGING WINDS AND LARGE HAIL WILL BE THE
PRIMARY THREATS FROM ANY STORMS THAT CAN BECOME SEVERE TONIGHT. BY
SUNRISE THE LINE SHOULD BE AT ABOUT THE BORDER WITH NC.
LONG TERM
(TUESDAY THROUGH SUNDAY)
ISSUED AT 256 AM EDT MON APR 14 2025
KEY MESSAGES:
1. LARGELY DRY THROUGH THE LONG TERM PERIOD. SOME SHOWERS MAY LINGER
IN THE MOUNTAINS TUESDAY MORNING, BUT OTHERWISE THE NEXT CHANCE OF
RAIN LOOKS TO BE THIS WEEKEND.
2. BELOW NORMAL THROUGH THURSDAY, THEN WARMING TO ABOVE NORMAL
FRIDAY INTO THE WEEKEND AS HIGH PRESSURE BUILDS ALOFT.
DISCUSSION:
A COLD FRONT WILL BE SOUTHEAST OF THE FORECAST AREA TO START THE
PERIOD TUESDAY MORNING, WITH UPSLOPE FLOW CONTINUING WELL INTO THE
AFTERNOON. GUIDANCE ISN'T OVERLY ENTHUSIASTIC ABOUT SHOWERS LINGERING
FOR TOO LONG BUT DID LEAVE SOME SLIGHT CHANCES IN THE TN MOUNTAINS
THROUGH MIDDAY OR SO AS WE'LL KEEP SOME JET ENERGY ALOFT UNTIL THE
AFTERNOON HOURS. SHORTWAVE ENERGY SHIFTS EAST OF THE AREA BY TUE
AFTERNOON BUT A LARGE SCALE TROUGH WILL REMAIN OVER THE EASTERN
CONUS THROUGH WEDNESDAY NIGHT BEFORE A BUILDING RIDGE TO OUR WEST
BEGINS TO PUSH IN. AS SUCH, COOLER CONDITIONS WILL CONTINUE TUE AND
WED BENEATH THE PERSISTENT NORTHWESTERLY UPPER FLOW.
BY EARLY THURSDAY MORNING UPPER HEIGHTS BEGIN TO BUILD AS THE RIDGE
PUSHES EAST THROUGH FRIDAY. WHILE THERE'S SOME DISCREPANCY WITH HOW
THE PATTERN UNFOLDS FRI INTO THE WEEKEND, I WOULD EXPECT FRI TO BE
DRY GIVEN HOW THE RIDGE IS BUILDING IN. TRENDS IN GUIDANCE CONFIRM
THIS, WITH RAIN CHANCES NOW BELOW MENTIONABLE LEVELS FRI. SATURDAY
MAY WIND UP BEING DRY AS WELL DEPENDING ON HOW THE PATTERN EVOLVES.
A NORTHERN STREAM TROUGH WILL MOVE EAST THROUGH THE CANADIAN SIDE OF
THE GREAT LAKES REGION FRI NIGHT INTO SAT, FLATTENING THE
AFOREMENTIONED RIDGE AND PUSHING A COLD FRONT INTO KENTUCKY TO OUR
NORTHWEST. THAT SAID, THERE'S SOME UNCERTAINTY HERE WITH HOW FAR
SOUTH THE FRONT MAKES IT AS THE RIDGE HOLDS STRONG ACROSS THE
SOUTHEAST AND ACTUALLY BUILDS NORTHWARDS ON SUN AS THE GREAT LAKES
DISTURBANCE CONTINUES EASTWARD INTO THE ATLANTIC. AS SUCH THE NBM
DEPICTION OF SLIGHT CHANCE POPS NEAR/JUST SOUTH OF THE I-40 CORRIDOR
AND CHANCE POPS IN THE NORTH FOR SAT SEEMS REASONABLE FOR THE TIME
BEING. BUT GIVEN THE PATTERN DEPICTED BY DETERMINISTIC MODEL RUNS, I
WOULDN'T BE AT ALL SURPRISED TO SEE RAIN CHANCES COME DOWN FURTHER
FOR SATURDAY. I COULD EASILY SEE WHERE THE RIDGE STRENGTH IS ENOUGH
TO HOLD THE FRONT NORTH OF US. REGARDLESS OF THE RAIN CHANCES THE
BUILDING RIDGE AND INCREASING SOUTHWESTERLY FLOW WILL PUSH
TEMPERATURE UP THE LOW 80S, OR ROUGHLY 8-10 DEGREES ABOVE NORMAL,
FOR FRI THROUGH SUN.
AVIATION
(12Z TAFS)
ISSUED AT 750 AM EDT MON APR 14 2025
THE WS THREAT AT TRI WILL DROP OFF SOON WITH ATMOSPHERIC MIXING.
SWLY GUSTS WILL INCREASE AT ALL TERMINALS AROUND MID-MORNING.
GUSTS FORECAST TO DROP OFF AT CHA, BUT WILL REMAIN ELEVATED AT TYS
AND TRI TONIGHT. DIRECTION WILL BECOME WESTERLY TO NORTHWESTERLY
IN THE LAST 6 HOURS OF THE PERIOD. PROB30 AT ALL TERMINALS FOR
LAST FEW HOURS OF THE TAF TO REFLECT CHANCES OF SHOWERS MOVING IN
WITH THE FRONT. SO FAR, NOT EXPECTING ANY VSBY OR CIG
RESTRICTIONS. BEST CHANCE OF THUNDER WILL BE FURTHER NORTH, BUT
CONFIDENCE IS LOW FOR ADDING IT AT TRI. OTHERWISE, VFR SHOULD
GENERALLY BE EXPECTED WITH MID AND HIGH CLOUDS DURING THE DAY.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 84 56 68 42 / 0 40 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 81 54 64 40 / 0 60 0 0
OAK RIDGE, TN 81 53 64 40 / 0 60 0 0
TRI CITIES AIRPORT, TN 77 51 60 39 / 0 70 10 0
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...KS
LONG TERM....CD
AVIATION...KS
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