Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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FXUS64 KMRX 041852
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
252 PM EDT TUE AUG 4 2015

.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...STRAY ISOLATED CONVECTION
MAY LINGER OVER MAINLY NORTHERN AREAS THIS EVENING BUT SHOULD
DISSIPATE BY SUNSET.  OTHERWISE...IT SHOULD BE A DRY NIGHT.  PATCHY
FOG IS POSSIBLE OVER NORTHERN AREAS WHERE RECENT RAINFALL HAS
OCCURRED.  WILL SEE A BETTER CHANCE OF CONVECTION ON WEDNESDAY
AFTERNOON AS LOW LEVEL MOISTURE CONTINUES TO INCREASE AND THE AIR
MASS BECOMES A BIT MORE UNSTABLE.  A WEAK SHORT WAVE RIDING ALONG
THE UPPER FLOW WILL MOVE IN DURING THE DAY ON WEDNESDAY AND WILL
ALLOW OF MORE WIDESPREAD CONVECTION.   COVERAGE SHOULD BE SCATTERED
WITH THE MAIN FOCUS ALONG A BOUNDARY STRETCHED OVER THE REGION.
TEMPERATURES WILL REMAIN NEAR SEASONAL NORMS WITH HIGHS REACHING
INTO THE UPPER 80S TO LOW 90S ACROSS THE TN VALLEY.

.LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY NIGHT)...THE MOST
CONSISTENT FEATURE THE MODELS OFFER STILL LOOKS TO BE A SHORTWAVE
TROUGH APPROACHING FROM THE MID-MS VALLEY REGION THURSDAY. A SURFACE
LOW AND ASSOCIATED COLD FRONT ACCOMPANY THE TROUGH...SO FELT IT WAS
PRUDENT TO STAY WITH SOLID LIKELY TO LOW END CATEGORICAL POPS FOR
THURSDAY. THIS SHORTWAVE TROUGH AND COLD FRONT WOULD APPEAR TO
TRACK E OR SE OF THE SOUTHERN APPALACHIANS BY 06Z FRIDAY. KEPT RAIN
CHANCES AT LIKELY THROUGH THURSDAY EVENING IN LINE WITH PREVIOUS
GRIDS.

FOLLOWING THIS INITIAL SYSTEM...FELT THERE SHOULD BE AT LEAST A
BRIEF BREAK FRIDAY MORNING...BEFORE AN UPSTREAM WEAKER SHORTWAVE
DROPS SE INTO THE REGION. BY THE WEEKEND...THE UPPER RIDGE OVER THE
PLAINS STATES STARTS TO BUILD NE...WHICH SHOULD RESULT IN WARMER
TEMPS AND RAIN CHANCES BELOW CLIMO. SUPERBLEND GRIDS GENERALLY IN
LINE WITH THIS LIKELY SCENARIO WITH A FEW TWEAKS.

FOR TUESDAY/NEW DAY 7...THE GFS AND ECMWF DIFFER WITH THE GFS
SHOWING ANOTHER SLIGHTLY AMPLIFIED SHORTWAVE...WHILE ECMWF HAS JUST
NW FLOW ALOFT. DID NOT WANT TO INTRO DAY 7 WITH TOO HIGH OF POPS
JUST YET...BUT DID KEEP THE SUPERBLEND CHANCE POPS TUESDAY THEN
SLIGHT CHANCE POPS FOR TUESDAY NIGHT.

FOR TEMPS...COOLER DAYS WILL BE THURSDAY AND FRIDAY THEN WARMING UP
ABOVE CLIMO OVER THE WEEKEND INTO EARLY NEXT WEEK. GUIDANCE TEMPS
LOOKED REASONABLE.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN             72  94  72  87 /  10  30  30  70
KNOXVILLE MCGHEE TYSON AIRPORT, TN  70  91  70  85 /  10  30  30  70
OAK RIDGE, TN                       70  91  71  85 /  20  30  30  70
TRI CITIES AIRPORT, TN              66  88  67  82 /  20  30  20  70

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

MJB/TG



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