736
FXUS64 KMRX 180121 AAA
AFDMRX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
921 PM EDT THU APR 17 2025
..NEW UPDATE
UPDATE
ISSUED AT 919 PM EDT THU APR 17 2025
THE FORECAST IS IN GOOD SHAPE THIS EVENING WITH QUIET WEATHER
UNDERNEATH A BUILDING MID/UPPER LEVEL RIDGE. AS THE RIDGE BUILDS
OVER THE REGION, HIGH CLOUDS ACROSS NE TN AND SW VA WILL BE
PUSHED NORTHEAST, AND MOST OF TONIGHT AND TOMORROW WILL HAVE CLEAR
SKIES. IN THIS DRY AIR MASS, WE WILL HAVE LOWS IN THE 50S TONIGHT
WITH HIGHS TOMORROW IN THE 80S.
SHORT TERM
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 225 PM EDT THU APR 17 2025
KEY MESSAGES:
1. DRY WITH WARMING TREND CONTINUING.
2. SOUTHWEST WINDS BEGIN TO INCREASE FRIDAY AFTERNOON.
DISCUSSION:
SURFACE HIGH PRESSURE SHIFTS TO THE EAST TONIGHT AND FRIDAY WITH
LOW PRESSURE ACROSS THE UPPER MISSISSIPPI VALLEY. THE INCREASING
PRESSURE GRADIENT WILL RESULT IN SOUTHWESTERLY WINDS INCREASING ON
FRIDAY AFTERNOON. OTHERWISE, DRY AIR REMAINS ACROSS THE REGION
WITH LOW RH VALUES. WITH THE INCREASING WINDS ON FRIDAY
AFTERNOON, THERE WILL BE AN ELEVATED WILDFIRE SPREAD RISK FRIDAY
AFTERNOON THAT WE WILL HIGHLIGHT IN THE FWF.
LONG TERM
(FRIDAY NIGHT THROUGH NEXT THURSDAY)
ISSUED AT 225 PM EDT THU APR 17 2025
KEY MESSAGES:
1. DRY AND WARMING THIS WEEKEND. HIGH CLOUDS INCREASE LATE WEEKEND
AHEAD OF A LOW PRESSURE SYSTEM.
2. INCREASING CONFIDENCE IN FRONTAL PASSAGE ON MONDAY WITH CHANCES
FOR SHOWERS AND THUNDERSTORMS. OVERALL SEVERE RISK IS LOW BECAUSE
OF MINIMAL INSTABILITY.
3. SUBTROPICAL HIGH PRESSURE AND ZONAL FLOW BEHIND THE FRONT MEANS
MORE NEAR NORMAL TO ABOVE NORMAL TEMPERATURES NEXT WEEK.
4. INCREASING CONVECTIVE CHANCES WEDNESDAY/THURSDAY AS SOUTHWEST
FLOW BRINGS INCREASING MOISTURE AHEAD OF A SHORTWAVE TROUGH.
DISCUSSION:
STRONG 592 DAM 500MB RIDGE ACROSS SOUTH GEORGIA AND NORTHERN
FLORIDA WILL HELP TO KEEP US DRY THIS WEEKEND WITH WARM AIR ALOFT
AND LIMITED INSTABILITY. CONVECTION, AND SEVERE WEATHER CHANCES,
REMAIN TO OUR WEST CLOSER TO THE MISSISSIPPI RIVER VALLEY.
BY MONDAY, THIS RIDGE IS EXPECTED TO FLATTEN IN RESPONSE TO THE
STRONG SHORTWAVE WHICH WILL ALLOW A WEAK COLD FRONT TO MOVE ACROSS
THE REGION WITH SHOWERS AND THUNDERSTORMS. WITH LIMITED HEIGHT
FALLS, OVERALL INSTABILITY IS LOW. THE GFS SHOWS MLCAPE LESS THAN
500 J/KG DURING THE AFTERNOON WITH 40 TO 50 KT EBSHEAR VALUES.
THE OVERALL SEVERE RISK IS LOW, BUT THE STRONGER STORMS COULD BE
CAPABLE OF DAMAGING WIND GUSTS SINCE GRADIENT WINDS AT AROUND 5000
FT WILL BE NEAR 40 KT. ANY THUNDERSTORM DOWNDRAFT WOULD PRESENT A
RISK OF STRONG WINDS.
WE DRY OUT ON TUESDAY WITH CLEARING CONDITIONS AND ZONAL FLOW
ALOFT RESULTING IN NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES
ACROSS THE REGION. HIGH PRESSURE QUICKLY SLIDES EAST OF THE
SOUTHERN APPALACHIANS BY WEDNESDAY WITH SOUTHWEST FLOW RETURNING.
THIS WILL LIFT THE FRONTAL BOUNDARY TO OUR SOUTH BACK NORTH ACROSS
THE REGION AS A WARM FRONT WITH SCATTERED SHOWERS AND
THUNDERSTORMS LATE WEDNESDAY INTO WEDNESDAY NIGHT. A NOTABLE
SHORTWAVE WILL RESULT IN HEIGHT FALLS AND ADDITIONAL INSTABILITY
FOR SCATTERED CONVECTION NEXT THURSDAY. EXACT FORECAST SOLUTIONS
ARE STILL UNCERTAIN, BUT THE GFS FORECAST MLCAPE OF AROUND 1000
J/KG AND EBSHEAR AROUND 15 TO 25 KT WOULD SUPPORT PRIMARILY
MULTICELL CONVECTION WITH PRIMARILY GUSTY WIND HAZARDS.
AVIATION
(00Z TAFS)
ISSUED AT 703 PM EDT THU APR 17 2025
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD. WINDS WILL BECOME
GUSTY TOMORROW AFTERNOON.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 53 85 59 87 / 0 0 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 50 83 59 86 / 0 0 0 0
OAK RIDGE, TN 49 82 58 84 / 0 0 0 0
TRI CITIES AIRPORT, TN 43 81 52 84 / 0 0 0 0
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...DGS
LONG TERM....JB
AVIATION...DGS
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