300
FXUS64 KMRX 030304
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1004 PM EST SUN FEB 2 2025
..NEW UPDATE
UPDATE
ISSUED AT 1001 PM EST SUN FEB 2 2025
OVERALL, THERE IS FAIRLY MINIMAL CHANGE WITH THE EVENING UPDATE.
TEMPERATURES HAVE BEEN VARIED THIS EVENING BASED ON THE PRESENCE
(OR ABSENCE) OF WIND. THESE VALUES WERE STILL UPDATED BASED ON
THE LATEST MODEL GUIDANCE. WINDS HAVE PERSISTED ACROSS THE
MAJORITY OF STATIONS DUE TO THE MSLP GRADIENT. THIS HAS LED TO A
SLIGHT INCREASE IN OVERNIGHT LOWS AND LESSER CONFIDENCE IN MORNING
FOG DEVELOPMENT, WHICH IS MOST LIKELY AROUND RIVER VALLEYS.
OTHERWISE, THE FORECAST WAS KEPT LARGELY THE SAME.
SHORT TERM
(THIS EVENING THROUGH MONDAY)
ISSUED AT 241 PM EST SUN FEB 2 2025
KEY MESSAGES:
1. VALLEY AND RIVER FOG POSSIBLE TONIGHT AND MONDAY MORNING.
2. WARM AND MOSTLY SUNNY FOR MONDAY.
DISCUSSION:
THE CURRENT PATTERN OF SURFACE HIGH PRESSURE TO OUR EAST, LOW
PRESSURE TO OUR NW, AND A NEARLY ZONAL FLOW ALOFT WILL REMAIN FAIRLY
STEADY-STATE THROUGH MONDAY. FOG IS LIKELY TO FORM ONCE AGAIN
TONIGHT, ALTHOUGH CONFIDENCE IN WIDESPREAD DENSE FOG IS LOWER
THAN YESTERDAY. THE NAM AND HRRR ARE POINTING TOWARD THE CENTRAL
VALLEY AS THE MAIN AREA FOR FOG DEVELOPMENT, AND ALONG AREA LAKES
AND RIVERS. WILL FOLLOW THIS GUIDANCE AS IT DID WELL LAST NIGHT.
HOWEVER, THERE MAY BE A LITTLE BETTER PRESSURE GRADIENT TONIGHT,
WHICH COULD PRODUCE JUST ENOUGH MIXING TO LIMIT FOG DEVELOPMENT IN
SOME SPOTS. MONDAY WILL BE PRETTY SIMILAR TO TODAY, JUST WARMER
AND LIKELY MORE SUNSHINE STARTING AT DAYBREAK; HIGHS WILL BE IN
THE 65 TO 70 RANGE ACROSS MOST OF THE TN VALLEY.
LONG TERM
(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 241 PM EST SUN FEB 2 2025
KEY MESSAGES:
1. UNSEASONABLY WARM NEXT WEEK, ESPECIALLY TUESDAY THROUGH THURSDAY.
2. RAIN CHANCES RETURN TO THE REGION FOR THE SECOND HALF OF THE
WEEK.
3. LOCALLY HEAVY RAIN IS POSSIBLE FOR WEDNESDAY AFTERNOON THROUGH
THURSDAY EVENING. LOCALIZED FLOODING POSSIBLE.
DISCUSSION:
FOR THE MAJORITY OF THE EXTENDED PERIOD, UPPER-LEVEL FLOW WILL
EXHIBIT A QUASI-ZONAL PATTERN, INTERRUPTED AT TIMES BY FAST MOVING
SHORTWAVES ACROSS THE TENNESEE AND OHIO VALLEYS. MULTIPLE JET
STREAKS WILL MOVE ACROSS THE OHIO AND TENNESSEE VALLEYS WILL PRODUCE
ROUNDS OF CONVECTION COMMENCING FROM WEDNESDAY AND PERSISTING
THROUGH SATURDAY.
TUESDAY:
PREDOMINANTLY DRY CONDITIONS. A FRONTAL BOUNDARY WITH LIMITED
MOISTURE WILL MOVE INTO SOUTHWEST VIRGINIA BY LATE TUESDAY. THERE
EXISTS A SMALL CHANCE OF SHOWERS. UNSEASONABLY WARM TEMPERATURES
WITH HIGHS SOME 15 TO 20 DEGREES ABOVE NORMAL.
WEDNESDAY THROUGH THURSDAY EVENING:
QUASI-STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS SOUTHWEST
VIRGINIA AND EAST TENNESSEE. A SERIES OF JET STREAKS TRAVERSING THE
OHIO AND TENNESSEE VALLEYS WILL ENHANCE FRONTOGENETIC FORCING ALONG
THIS BOUNDARY, RESULTING IN INTERMITTENT SHOWERS AND THUNDERSTORMS.
ENSEMBLE CAPE VALUES AROUND 500 J/KG SUGGEST THE POTENTIAL FOR
EMBEDDED THUNDERSTORMS.
ADDITIONALLY, PRECIPITABLE WATER VALUES WILL RISE TO 1-2 STANDARD
DEVIATIONS ABOVE THE SEASONAL NORMALS, WHICH INCREASES THE THREAT
FOR LOCALIZED HEAVY RAINFALL ASSOCIATED WITH THE THUNDERSTORMS.
ENVIRONMENT WILL ALSO BE CONDUCIVE FOR FAVORABLE WARM RAIN PROCESS
GIVEN THE UNSEASONABLY MILD TEMPERATURES AND HIGH FREEZING LEVELS.
GIVEN THE ORIENTATION OF THE BOUNDARY AND UPPER FLOW ARE
PARALLEL, TRAINING OF STORMS ARE POSSIBLE ENHANCING THE THREAT OF
LOCALIZED FLASH FLOODING.
HOWEVER, NBM'S 24-HOUR PROBABILITIES FOR PRECIPITATION EXCEEDING 1
INCH REMAIN AT ONLY 40-50% FOR SOUTHWEST VIRGINIA. WIDESPREAD
FLOODING STILL APPEARS LOW AT THIS TIME.
FRIDAY:
A SMALL BREAK IN CONVECTION IS ANTICIPATED AS THE JET STREAK
MIGRATES EASTWARD. FORECAST CONFIDENCE REGARDING THE TIMING OF THESE
WAVES IS LOW.
SATURDAY AND SUNDAY:
ANOTHER JET STREAK IS PROJECTED TO INTENSIFY SOUTHERLY
BOUNDARY LAYER FLOW, LEADING TO AN INCREASED LIKELIHOOD OF
CONVECTION. ISENTROPIC LIFT IS EXPECTED ESPECIALLY ON SATURDAY AS A
WARM FRONT LIFTS NORTH. A STRONG FRONTAL BOUNDARY IS EXPECTED TO
MOVE ACROSS NEXT SUNDAY.
DAILY RECORD HIGH MAXIMUM TEMPERATURES
DATE CHATTANOOGA KNOXVILLE TRI-CITIES OAK RIDGE
02-03 75(1986) 74(2020) 74(1989) 71(2020)
02-04 77(1927) 72(1986) 68(1986) 68(1992)
02-05 75(1890) 73(2008) 71(2008) 71(2019)
02-06 70(2019) 73(1986) 68(1991) 70(2008)
02-07 80(2019) 77(2019) 76(2019) 76(2019)
02-08 76(1937) 75(1937) 70(2001) 71(2009)
AVIATION
(00Z TAFS)
ISSUED AT 601 PM EST SUN FEB 2 2025
GUSTY WINDS WILL DECREASE OVERNIGHT WITH SOME LIGHT WINDS LIKELY
CONTINUING AT CHA AND TRI. AT TYS, HOWEVER, THERE WILL BE ANOTHER
HIGH PROBABILITY OF FOG DEVELOPMENT BY EARLY MONDAY MORNING.
REDUCTIONS TO IFR WERE MAINTAINED IN THE TAF, BUT LIFR OR LOWER
CONDITIONS ARE DEFINITELY POSSIBLE. IF FOG OCCURRED AT ANOTHER
SITE, CHANCES MAY BE SLIGHTLY HIGHER AT TRI, BUT TYS IS THE MAIN
CONCERN FOR FOG. DURING THE DAY ON MONDAY, VFR CONDITIONS AND A
BREEZY SOUTHERLY WIND CAN BE EXPECTED.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 42 71 49 71 / 0 0 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 40 68 50 68 / 0 0 0 10
OAK RIDGE, TN 41 67 49 67 / 0 0 0 0
TRI CITIES AIRPORT, TN 36 66 46 63 / 0 0 0 10
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...DGS
LONG TERM....DH
AVIATION...BW
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