Severe Thunderstorm Warning 140, NWS Morristown, TN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
925 AM EDT THU MAY 15 2003

THE FOLLOWING ARE ALL THE FORECAST DISCUSSIONS FROM THE PAST 24
HOURS...WITH THE MOST RECENT ON TOP. THIS PROVIDES A HISTORY OF THE
DEVELOPMENT OF THE CURRENT FORECAST.
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LATE MORNING FORECAST DISCUSSION (UPDATE)
925 AM EDT THU MAY 15 2003

SATELITTE SHOWS A SHORT-WAVE MOVING EAST-SOUTHEAST ACROSS THE
OHIO VALLEY.  ONE LOBE OF ENERGY MOVING ACROSS EASTERN KENTUCKY
PRODUCING AN AREA OF SHOWERS AND THUNDERSTORMS.  ANOTHER WAVE
IS MOVING ACROSS IL. SURFACE LOW IS LOCATED ACROSS SOUTHERN
IL.  MESO-ETA SHOWS A 90-100 KNOT 300 MB JET MOVING ACROSS
THE MID-SECTION OF THE NATION WITH THE OHIO AND TENNESSEE
VALLEYS UNDER THE INFLUENCE OF THE LEFT FRONT QUAD.

MSAS ANALYSIS SHOWS ATMOSPHERE ALREADY MODERATELY UNSTABLE ACROSS
MOST OF KENTUCKY AND NORTHERN SECTIONS OF TENNESSEE. MESO-ETA
SHOWS LIFTED INDICES DROPPING TO -6 TO -7 THIS AFTERNOON WITH
CAPES NEAR 2500 J/KG. WINDS ALOFT WILL BE FAIRLY WEAK...SO
STRAIGHT LINE WIND DAMAGE NOT EXPECTED...HOWEVER...PRESENCE
OF A MID-LEVEL DRYING SUGGEST POTENTIAL OF WET MICRO-BURSTS.

LEVEL OF WBZ WILL BE BETWEEN 9500-10500 FEET...SO POTENTIAL OF
LARGE HAIL ALSO EXISTS TODAY. PLAN ON INCLUDING SOME POSSIBLY
SEVERE FOR THIS AFTERNOON AND EVENING.

MAY UP POPS SOME...BUT OVERALL CURRENT FORECASTS LOOKS GOOD.

.MRX...
NC...NONE.
TN...NONE.
VA...NONE.

DH

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EARLY MORNING FORECAST DISCUSSION
325 AM EDT THU MAY 15 2003

CURRENT SURFACE ANALYSIS SHOWS A LOW PRESSURE AREA OVER CENTRAL
ILLINOIS AND INDIANA...WITH A WEAK COLD FRONT STRETCHING WEST AND
EAST OF IT NORTH OF THE OHIO RIVER. NUMEROUS SHOWERS AND TSTORMS ARE
ALREADY DEVELOPING ACROSS THE OHIO RIVER VALLEY...AND EXPECT THIS
ACTIVITY TO CONTINUE TO MOVE SOUTHEAST INTO THE FORECAST AREA TODAY.
THIS COLD FRONT AND AN UPPER TROUGH IS EXPECTED TO MOVE ACROSS THE
FORECAST AREA THIS AFTERNOON...WITH A MODERATELY UNSTABLE AIRMASS
ALLOWING FOR THE POSSIBILITY OF SOME SEVERE TSTORMS WITH DAMAGING
WINDS AND LARGE HAIL. THIS COLD FRONT SHOULD MOVE THROUGH MOST OF THE
AREA BY THIS EVENING...AND BECOME QUASI-STATIONARY OVER THE DEEP
SOUTH ON FRIDAY. WITH THIS FRONTAL PASSAGE...A TEMPORARY BREAK IN
CONVECTION IS EXPECTED ACROSS THE FORECAST AREA LATER TONIGHT UNTIL
FRIDAY AFTERNOON...WHEN INSTABILITY AND MOISTURE RETURN TO PRODUCE A
FEW SCATTERED AFTERNOON AND EVENING TSTORMS. THE STATIONARY FRONT
OVER THE DEEP SOUTH IS PROGGED TO MOVE NORTH AS A WARM FRONT ON
SATURDAY...AS A LOW PRESSURE SYSTEM DEVELOPS OVER THE LOWER
MISSISSIPPI VALLEY. THIS SYSTEM WILL KEEP THE CHANCE FOR ADDITIONAL
CONVECTION IN THE FORECAST THROUGH THE WEEKEND...AS THIS LOW MOVES
INTO THE SOUTHERN APPALACHIAN REGION ON SUNDAY.

AS FOR TEMPS...NGM AND GFS GUIDANCE NUMBERS ARE IN GOOD AGREEMENT
THROUGH FRIDAY AND LOOK REASONABLE. WILL TREND TOWARD A COMPROMISE
BETWEEN THE TWO ON FRIDAY NIGHT.

THE FOLLOWING NUMBERS ARE PRELIMINARY AND FOR COORDINATION ONLY:

CHA   77  60  83  63 /  60  40  40  40
TYS   74  59  80  63 /  60  40  30  40
TRI   71  55  78  60 /  60  40  20  40
OQT   74  59  80  63 /  60  40  30  40

DMG

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EVENING FORECAST DISCUSSION (UPDATE)
900 PM EDT WED MAY 14 2003

NOT ENOUGH OF A TREND TO HANG AN UPDATE ON TONIGHT.  SOUTHERLY WINDS
CONTINUE TO PUMP MOISTURE INTO THE REGION AS A WARM WARM MOVES
ACROSS THE AREA.  SHOWERS JUST TO THE WEST OF THE FORECAST AREA
APPEAR TO BE WEAKENING...HOWEVER CANNOT RULE OUT RE-DEVELOPMENT
OVERNIGHT.  CURRENT LIKELY FORECAST FOR THE SOUTHERN HALF OF THE
AREA MAY BE A LITTLE STRONG...BUT NOT ENOUGH INFORMATION FOR ME TO
CHANGE AT THIS TIME.  TEMPERATURE FORECASTS APPEAR TO BE REASONABLE.
NO CHANGES PLANNED.

********************************************************************
AFTERNOON FORECAST DISCUSSION
330 PM EDT WED MAY 14 2003

A WEAK SHORT WAVE WILL PASS ACROSS THE REGION OVERNIGHT ALLOWING
SOME SHOWERS AND THUNDERSTORMS TO OCCUR...UNTIL THE UPPER LEVEL
TROUGH PASSES THROUGH THURSDAY MORN INTO THE EVENING ALLOWING FOR
MORE WIDESPREAD COVERAGE OF RAINFALL...MORE INSTABILITY WILL GIVE A
GREATER CHANCE OF THUNDERSTORMS THURSDAY AFTN AND EVENING. EARLY
FRIDAY MORNING SOME WEAK RIDGING WILL BUILD INTO THE TN
VALLEY...ALLOWING FOR A PARTLY CLOUDY DAY WITH WARMER TEMPS.

THE WEEKEND SHOWS A WET PATTERN SETTING UP AS A SLOW MOVING UPPER
LOW WILL WORK ITS WAY OUT OF THE EASTERN PLAINS ACROSS THE MID
SOUTH. RAINFALL MAY BE HEAVY AT TIMES AND WITH THE MOIST SOIL MAY BE
PROBLEMATIC FOR FLOODING. STILL SOME UNCERTAINTY ON THE EXACT
LOCATION OF MAX RAINFALL ACROSS THE TN VALLEY AND LOCAL MOUNTAINOUS
AREAS. MAY INVOLVE STRONG STORMS FOR SAT AFTN.

SOME DISCREPANCIES IN THE MODELS ON THE PRECIP FOR EARLY THURS WENT
WITH MODERATE VALUES AS GOOD LIFT SHOWING UP...FAIRLY GOOD AGREEMENT
FOR THE MODELS FOR REST OF EARLY PERIODS....MOS TEMPS HAVE VERY
LITTLE DIFFERENCES...WENT COOLER FOR HIGHS THURS WITH CLOUDY SKIES
AND WARMER FOR LOWS FOR THE SAME REASONING. REST OF TEMPS BLENDED.

THE FOLLOWING NUMBERS ARE PRELIMINARY AND FOR COORDINATION ONLY:
CHA   61  76  61  83 /  70  60  40  10
TYS   60  74  60  81 /  60  60  50  10
TRI   55  68  57  76 /  50  70  60  20
OQT   59  73  59  81 /  60  60  50  10

BS

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-005-
006-008-161000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
534 AM EDT THU MAY 15 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST TENNESSEE...SOUTHWEST
VIRGINIA AND EXTREME SOUTHWEST NORTH CAROLINA.

.DAY ONE (TODAY)...

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS TODAY.  A SURFACE
FRONT WILL MOVE THROUGH THE AREA TODAY.  WITH THE UNSTABLE
ATMOSPHERE...SEVERE THUNDERSTORMS WILL BE POSSIBLE...MAINLY THIS
AFTERNOON AND EVENING.  THE MAIN THREATS WITH ANY STORMS WILL BE
LARGE HAIL AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN (FRIDAY THROUGH WEDNESDAY)...

THERE WILL ALSO BE A CHANCE FOR STRONG TO SEVERE STORMS ON SATURDAY
AND SUNDAY...AS AN UPPER LEVEL TROUGH PASSES OVER THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY...AND AGAIN THIS WEEKEND.

PLEASE STAY TUNED TO NOAA WEATHER RADIO OR VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/MRX.

GH