-- Discussion containing changed information from previous version are highlighted. --
000
FXUS64 KMRX 210752
AFDMRX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
352 AM EDT TUE MAY 21 2013

.SHORT TERM...
-- Changed Discussion --
(TODAY THROUGH WEDNESDAY NIGHT)...EARLY MORNING DENSE
FOG ACROSS MAINLY SOUTHWEST VIRGINIA AND NORTHEAST TENNESSEE.
CURRENTLY COVERAGE IS SCATTERED...PER SATELLITE/OBS...BUT WILL
MONITOR FOR POTENTIAL ADVISORY.

A LINE OF STORMS IS CURRENTLY ACROSS FAR WESTERN TENNESSEE. LATEST
NAM SUGGEST THE OUTFLOW BOUNDARY FROM THIS CONVECTION WILL MOVE
ACROSS TENNESSEE THIS MORNING/EARLY AFTERNOON AND BE LOCATED OVER
THE PLATEAU BY 16-18Z. AIRMASS WILL BE MODERATELY UNSTABLE WITH
CAPES OF 2000-2500 J/KG..SO SCATTERED TO BROKEN CONVECTION
ANTICIPATED ALONG THIS BOUNDARY AS WELL AS ALONG TERRAIN FEATURES.
A GOOD DEAL OF MID-LEVEL DRY AIR WILL PROMOTE DRY AIR ENTRAINMENT
INTO THE DOWNDRAFTS WITH DAMAGING WINDS A CONCERN. ALSO...WET BULB
ZERO HEIGHTS AND HAIL CAPE VALUES WILL BE FAVORABLE FOR MARGINAL
LARGE HAIL. HAVE INCLUDED WITHIN THE HWO.

CONVECTION WILL DIMINISH THIS EVENING DUE TO LOSS OF DAYTIME
HEATING.

FOR WEDNESDAY...AN APPROACHING FRONT AND LIKELY OUTFLOW BOUNDARIES
COMBINED WITH MARGINAL INSTABILITY WILL PRODUCE SCATTERED TO BROKEN
CONVECTION. MODELS CURRENTLY DO NOT FAVOR AN OUTBREAK OF SEVERE WEATHER..BUT
GIVEN THE INCREASING MID-LEVEL WINDS ASSOCIATED WITH UPPER TROUGH
OVER THE MID-WEST..WE WILL HAVE TO MONITOR FOR THE POSSIBILITY OF STRONG-
SEVERE STORMS.

.LONG TERM (THURSDAY THROUGH MONDAY)...UPPER TROUGH AMPLIFIES
THURSDAY INTO FRIDAY MAKING SLOW PROGRESS AS IT SHIFTS FROM THE
MISSISSIPPI VALLEY TO THE EASTERN SEABOARD BY 00Z SATURDAY. BUMPED
POPS UP SLIGHTLY ON THURSDAY WITH A COLD FRONT BUILDING THROUGH THE
SOUTHERN APPALACHIANS. MAINTAINED SOME CHANCE POPS THURSDAY NIGHT
TAPERING TO SLIGHT CHANCE ON FRIDAY AS MODELS INDICATE A FAIR AMOUNT
OF SHORT WAVE ENERGY AND DEEP MOISTURE ROTATING THROUGH THE EASTERN
U.S. LONG WAVE. STAYED WITH CONVECTION ON THURSDAY BUT WITH
INCREASING STABILITY THURSDAY NIGHT INTO FRIDAY USED SHOWER WORDING.
PREVAILING NORTHWEST FLOW WITH DRY ADVECTION AND A NICE EXPANSIVE
SURFACE RIDGE SHOULD ALLOW FOR A DRY PERIOD SATURDAY THROUGH SUNDAY.
GFS/CMC HINT AT THE PASSAGE OF A SHORT WAVE SUNDAY NIGHT INTO MONDAY
WITH LOW LEVEL WARM AND MOIST ADVECTION DEVELOPING ON THE BACK SIDE
OF THE DEPARTING RIDGE. THEREFORE KEPT A SLIGHT CHANCE FOR A SHOWER
SUNDAY NIGHT WITH THE POSSIBILITY OF A THUNDERSTORM ON
MONDAY.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
CHATTANOOGA AIRPORT, TN             88  65  85  63  84 /  30  30  60  50  30
KNOXVILLE MCGHEE TYSON AIRPORT, TN  87  65  84  63  81 /  30  30  50  50  40
OAK RIDGE, TN                       87  65  84  62  80 /  30  20  50  50  40
TRI CITIES AIRPORT, TN              85  59  84  59  77 /  20  20  60  50  50
-- End Changed Discussion --

&&

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

&&

$$