Severe Thunderstorm Warning 2, NWS Glasgow, MT

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
229 PM MDT TUE MAY 13 2003

.SHORT TERM...TONIGHT THROUGH FRIDAY...
ETA AND AVN LOOK TO BE IN GOOD AGREEMENT WITH FEATURES AT THE SFC
AND ALOFT FOR THE NEXT COUPLE OF DAYS. SHORT WAVE ENERGY EXITING OUR
EASTERN ZONES IS IN THE PROCESS OF CARVING OUT A CUT-OFF LOW WHICH
WILL DEVELOP THIS EVENING ACROSS CENTRAL AND WESTERN ND. WILL
MAINTAIN A CHANCE OF SHOWERS AND T-SHOWERS THROUGH 03Z ACROSS OUR
EASTERN ZONES FOR THIS FEATURE. ADDITIONAL CONVECTION HAS FIRED UP
WITHIN THE LAST HOUR ALONG A COUPLE OF WEAK BOUNDARIES...AND THERE
HAVE BEEN A FEW REPORTS OF SMALL HAIL IN NORTHERN PHILLIPS AND
EASTERN VALLEY COUNTIES. EXPECT THIS CONVECTION WILL DIE DOWN BY
SUNSET. WILL ADD IN A MENTION OF ISOLATED T-SHOWERS EARLY TO ACCOUNT
FOR THE CONVECTION THAT FIRED UP THIS AFTERNOON.

UPPER RIDGE CURRENTLY OVER THE WESTERN PART OF THE STATE TO BUILD
EAST TONIGHT. GOOD MIXING THIS AFTERNOON AND WINDS ARE A BIT BUSY.
THE SFC GRADIENT WEAKENS THIS EVENING AND WE WILL DECOUPLE LATER
TONIGHT SO WINDS WILL DIMINISH.  EXPECT THAT WITH ALL THE RAIN OF
LATE...AND LOW LEVEL MOISTURE THAT PATCHY FOG IS A GOOD BET. WILL
NOT INCLUDE IN OUR WESTERN ZONES WHERE DRYING WAS BETTER THIS
AFTERNOON. THE UPPER RIDGE BUILDS INTO EASTERN MT TOMORROW FOR A DRY
AND SUNNY DAY.  ATMOSPHERE COOLS IN THE WAKE OF THE DEPARTING
LOW...ESPECIALLY ACROSS EXTREME EASTERN MT. WARM ADVECTION KICKS IN
BY LATE TOMORROW MORNING AND THE MERCURY WILL RECOVER TO THE WARMEST
LEVELS IN THE LAST TEN DAYS. ETA SEVERAL DEGREES WARMER AT 850H
TOMORROW AND PLAN ON USING A BLEND OF OF THE TWO MODELS BUT LEANING
CLOSER TOWARDS THE WARMER ETA NUMBERS WHICH WOULD SUPPORT HIGHS IN
L/M 70S IN MOST SPOTS.

THE UPPER RIDGE AXIS CRESTS OVER THE AREA TOMORROW EVENING AND MOVES
INTO THE DAKOTAS THURSDAY. MODELS BRING A WEAK SFC TROUGH THROUGH
THE AREA THURSDAY AFTERNOON WITH WEAK OVERRUNNING AND A BAND OF
MOISTURE. LOOKS TO BE ENOUGH MOISTURE AND LIFT TO TOUCH OFF WIDELY
SCATTERED SHOWERS...ESPECIALLY IN OUR EASTERN ZONES WHERE DIURNAL
HEATING SHOULD AID LIFT. LIS ARE PROGGED TO DROP TO 0 TO -2C
THURSDAY AFTERNOON ACROSS OUR SOUTHEAST ZONES AND INHERITED FCST
WHICH MENTIONS THUNDER LOOKS GOOD.  MOISTURE SHIFTS OFF TO THE EAST
THURSDAY NIGHT WITH WEAK SUBSIDENCE. WILL MAINTAIN A CHANCE OF
SHOWERS INTO THE EVENING...BUT DRY IT OUT OVERNIGHT. ON FRIDAY WE
HAVE A BROAD SW FLOW AROUND AN UPPER TROUGH MOVING INTO THE PACIFIC
NORTHWEST WITH A BROAD TROUGH OF LOW PRESSURE ACROSS EASTERN MT.
BEST CHANCE OF CONVECTION LOOKS TO BE DURING THE AFTERNOON ACROSS
OUR EASTERN ZONES WHERE THERE WILL BE THE GREATEST INSTABILITY. WILL
UPDATE THE GRIDS TO REFLECT THE HIGHER CHANCE ACROSS OUR SE
ZONES...BUT OTHERWISE NOT PLANNING ON ANY CHANGES TO INHERITED
FORECAST FOR FRIDAY. CB

.LONG TERM...
MEDIUM RANGE MODELS IN GOOD AGREEMENT THROUGH THE EXTENDED PERIOD.
UKMET THE ONE OUTLIER. MAIN FEATURE IS UPPER TROF DIGGING ALONG
PACIFIC NORTHWEST COAST SATURDAY THEN ROTATING THROUGH MONTANA EARLY
NEXT WEEK. SURFACE FRONT TRACKING ACROSS THE CWA ON FRIDAY STALLS
OVER DAKOTAS SATURDAY AND SUNDAY. SOUTHWEST FLOW ALOFT AHEAD OF THE
UPPER TROF SENDS WEAK IMPULSES ALONG THE FRONTAL BOUNDARY KEEPING
CHANCE OF THUNDERSTORMS MAINLY OVER EASTERN ZONES FRIDAY NIGHT.
CHANCE OF SHOWERS INCREASES LATE SATURDAY INTO SUNDAY WITH THE UPPER
TROF MOVING EAST AND A STRONGER WAVE DEVELOPING IN WYOMING ALONG THE
FRONT. THUNDERSTORM THREAT WILL BE GREATEST OVER EASTERN ZONES AS
CLOSER TO THETA-E RIDGE. CHANCE OF SHOWERS CONTINUES MONDAY AND
TUESDAY AS THE UPPER TROF SWINGS ACROSS THE AREA. TEMPERATURES WILL
GENERALLY BE COOL THROUGH THE PERIOD WITH THE SOUTHEAST ZONES SEEING
THE WARMEST TEMPERATURES OVER THE WEEKEND. EBERT

KGGW UBE 041/076 044/072 045/069 92200222
     WWWR 042/060 040/059 039/059 041/059 9003333333
KGDV UBW 042/075 042/074 045/072 92200334
     WWWR 046/065 042/062 042/058 042/058 9033333333

.KGGW...NONE.

MTZ016>027-059>062-141200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
558 AM MDT TUE MAY 13 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST MONTANA

.DAY ONE...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.