650
FXUS64 KMRX 161141
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
741 AM EDT SAT OCT 16 2021
AVIATION
12Z TAF DISCUSSION.
RADAR INDICATES FRONT IS THROUGH CHA AND NEAR TYS NOW. WINDS
SHIFTING TO NORTHWESTERLY WITH THE FROPA, AND PRECIP WILL CONTINUE
TO BE USHERED EASTWARD OUT OF THE AREA THROUGH MORNING. SOME MVFR
CONDITIONS TEMPORARILY OCCURRING WITH THE PRECIP, AND WITH LOW
CLOUDS BEHIND THE FRONT. CONDITIONS WILL IMPROVE TO VFR FROM WEST
TO EAST THROUGH THE DAY AS DRY AIR MOVES IN.
GC
SHORT TERM (TODAY AND TONIGHT)
FROPA WILL OCCUR THROUGH THE AREA THIS MORNING, USHERING OUR
PRESENT BANDS OF SHOWERS EASTWARD. WE WILL OPEN THE PERIOD AT 12Z
WITH THE BULK OF THE SHOWERS OVER THE EASTERN HALF OF THE CWA,
AND BY THE AFTERNOON THERE WILL ONLY BE LINGERING SHOWERS NEAR THE
SPINE OF THE EASTERN MOUNTAINS, AS SKIES CLEAR OVER THE VALLEY AND
PLATEAU. WINDS WITH THE FROPA WILL BE A BIT BREEZY FROM THE WEST-
NORTHWEST TODAY, SUSTAINED 10-20 MPH. CONDITIONS WILL BE
NOTICEABLY COLDER AND DRIER TONIGHT IN COMPARISON TO OUR RECENT
MUGGY WARMTH. EXPECTING ENOUGH WINDS TO PERSIST OVER THE
MOUNTAINS TONIGHT SO AS TO MINIMIZE FROST OUTSIDE OF THE MOST
SHELTERED SPOTS.
GC
LONG TERM (SUNDAY THROUGH FRIDAY)
KEY MESSAGES:
1. DRY FOR MOST OF THE PERIOD WITH TEMPERATURES STARTING OUT BELOW
NORMAL ON MONDAY MORNING, WARMING THROUGH THE WEEK.
2. THE NEXT BEST CHANCE FOR CONVECTION IS ON THURSDAY NIGHT AND
FRIDAY MORNING AS THE NEXT FROPA OCCURS FOR THE REGION.
DISCUSSION:
THE LONG TERM FCST PERIOD KICKS OFF ON SUNDAY MORNING AMIDST THE
PASSAGE OF A LONGWAVE TROUGH AXIS OVER THE SOUTHERN APPALACHIANS
FOSTERING DEEP NWLY FLOW (CAA), ALL WHILE FULL-LATITUDE RIDGING
AMPLIFIES WESTWARD OVER THE ROCKIES/PLAINS. AT THE SURFACE,
CONFLUENCE ALOFT ATOP THE SOUTHERN PLAINS WILL FAVOR A NEARLY 1025MB
SFC RIDGE WHICH LOOKS TO EXTEND EAST THROUGH THE APPALACHIANS INTO
THE EASTERN SEABOARD. AT FCST INITIALIZATION, CAA WILL PREVAIL WITH
MODERATE WINDS (10-20MPH) AT THE HIGHER ELEVATIONS SLOWLY TAPERING
AS PGFS LOOK TO RELAX THROUGH MORNING AMIDST BELOW NORMAL
TEMPERATURES THROUGHOUT THE DAY. SUNDAY NIGHT'S WINDS SHOULD BE
WEAKER AS THE UPPER RIDGE AXIS SHIFTS EAST ALLOWING THE SFC RIDGE TO
CENTER ITSELF NEARLY OVERHEAD FOSTERING CLEAR SKIES AND GOOD
RADIATIONAL COOLING CONDITIONS INTO MONDAY MORNING. WITH THAT, LOW
TEMPERATURES IN THE 30S/40S ARE FAVORED, COOLEST ACROSS NORTHEAST TN
AND SOUTHWEST VA WHERE EVEN SOME PATCHY FROST IS POSSIBLE BEFORE
TEMPERATURES WARM NICELY FOR THE AFTERNOON HOURS AMIDST MOSTLY SUNNY
CONDITIONS.
MOVING ON INTO TUESDAY AND THROUGH THE REST OF THE WEEK, THE BRIEF
OMEGA BLOCKING PATTERN LOOKS TO BREAK DOWN AS THE NORTHWESTERN CONUS
CYCLONE ADVANCES THROUGH THE ROCKIES AND THE NORTHEAST UPPER LOW
EJECTS INTO THE NORTH ATLANTIC, ALL ALLOWING THE H5 RIDGE AXIS TO
TRANSITION ATOP THE APPALCHIANS ON TUESDAY/WEDNESDAY. TEMPERATURE
TRENDS WILL BEGIN TO MODERATE DURING THIS TIMEFRAME AS THE SURFACE
RIDGE SLIDES EAST OF THE MOUNTAINS ACROSS THE CAROLINAS, THUS
EXPECTING NEARER NORMAL LEVELS BY MIDWEEK. AT THAT POINT THE FOCUS
SHIFTS TO THE LATE WEEK ACTIVITY AS THE NORTHERN ROCKIES H5 CYCLONE
ADVECTS EASTWARD OVER PLAINS INTO THE UPPER MIDWEST BY THURSDAY
MORNING, WITH A SURFACE COLD FRONT EXTENDING FROM LAKE SUPERIOR LOW
PRESSURE ALONG THE MS RIVER INTO THE MIDSOUTH REGION. OUT AHEAD,
WARM ADVECTION WILL CONTINUE ACROSS THE TN VALLEY REGION AS THE
EASTERN CONUS UPPER RIDGE AXIS DEAMPLIFIES. HEIGHTS WILL CONTINUE
TO FALL EASTWARD AS THE UPPER LOW/TROUGH MOVES IN THURSDAY NIGHT
INTO FRIDAY WITH A FROPA FAVORED OVERNIGHT INTO FRIDAY MORNING. AT
THIS RANGE CONFIDENCE IN COVERAGE AND INTENSITY IS LOW, HOWEVER
POSITIONING OF THE UPPER JET MAX SUGGEST AT LEAST SOME DIVERGENCE AS
THE RIGHT ENTRANCE REGION PIVOTS OVERHEAD. THUS WILL CARRY CHANCE
POPS THURSDAY NIGHT INTO FRIDAY MORNING, TAPERING SHARPLY POST FROPA
INTO THE AFTERNOON HOURS AS CAA PREVAILS YET AGAIN.
CDG
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 66 46 67 45 71 / 10 0 0 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 66 43 65 43 69 / 60 0 0 0 0
OAK RIDGE, TN 65 43 65 43 69 / 10 0 0 0 0
TRI CITIES AIRPORT, TN 66 39 61 39 66 / 70 0 0 0 0
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
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