FXUS65 KBYZ 300902
AFDBIL

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
302 AM MDT WED APR 30 2003

.SHORT TERM...VALID FOR TDY AND THU...

CURRENT FORECAST LOOKS TO HAVE A PRETTY GOOD HANDLE ON SITUATION.

GFS/ETA IN MUCH BETTER AGREEMENT TONIGHT COMPARED TO LAST NIGHT. WATER
VAPOR SHOWING PLENTY OF MOISTURE STREAMING UP FROM THE SOUTH AS JET
STREAM PUSHES ACROSS NEVADA AND NEW MEXICO. BOTH GFS AND ETA CLOSE OFF
WEAK UPPER LOW OVER NORTHERN WYOMING/SOUTHERN MONTANA BY THIS
AFTERNOON. THIS SETS UP GOOD AREA OF UPPER DIFFLUENCE ALONG MT/WY
BORDER DURING THE DAY...GFS IS A BIT FURTHER NORTH WITH THIS ENERGY.
ETA PROGGING DEEP MOISTURE AND GOOD LIFT AT 700 MB BULLS-EYED OVER
SHERIDAN COUNTY WYOMING DURING THE DAY WITH FREEZING LEVELS DROPPING
TO AROUND 6000 FEET...AND HEAVY SNOW WARNING LOOKS GOOD THERE. THIS
SEEMS TO LINE UP WITH CURRENT WV VERY WELL. ELSEWHERE TEMPERATURES LOOK
WARM ENOUGH FOR MAINLY RAIN...POSSIBLY SOME MIX IN EASTERN SLOPE AREAS
THIS MORNING. WILL TWEAK HIGHS A BIT DOWNWARD TODAY IN SOME AREAS.
BILLINGS LOOKS TO BE ON NORTHERN EDGE OF PRECIP TODAY...BUT WON'T
TOUCH CURRENT HIGH POPS.

TONIGHT...UPPER LOW SLOWLY DECREASES IN INTENSITY WITH LIFT DECREASING.
BUT SOUTHERN ZONES CONTINUE TO BE AREA OF BEST ENERGY AND WILL ONLY
TWEAK POPS HERE AND THERE. AGAIN...TEMPERATURES REMAIN PRETTY WARM
OVER PLAINS AND WILL KEEP PRECP MAINLY RAIN.

THURSDAY...SOME DIFFERENCES IN MODELS AS WOULD BE EXPECTED WITH COMPLEX
UPPER PATTERN. ETA LINGERS A 700 MB LOW IN SOUTHEAST MONTANA...WITH
GOOD MOISTURE FETCH CONTINUING FROM BILLINGS SOUTH AND EAST. BIGGEST
DIFFERENCE IS THE INCREASE OF SOME INSTABILITY IN WESTERN ZONES. WILL
INTRODUCE SOME AFTERNOON/EVENING THUNDER MENTION THERE AND KEEP GENERAL
UNSETTLED POPS GOING. WAS TEMPTED TO RAISE POPS A BIT...BUT
DUE TO UNCERTAINTY WILL LEAVE FORECAST AS IS. TEMPERATURES LOOK GOOD.
THANKS TO GGW/TFX FOR COORDINATION. RASCH

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...

UNSETTLED WEATHER LOOKS LIKE IT WILL CONTINUE THROUGH THE PERIOD.
LOOKING AT HOW THE UPPER LEVEL TROUGH ORIENTS ITSELF TO BECOME
NEGATIVELY TILTED...IT WOULD SEEM THAT PRECIPITATION ACTIVITY FOR
FRIDAY MAY NOT REACH THE NORTHEAST PART OF COUNTY WARNING AREA. MODELS
SHOW A SOUTHWEST FLOW OVER THE AREA THEN...BUT TIMING OF SHORT WAVES...
AS WELL AS THEIR STRENGTH IS THE PROBLEM AREA THEN. SATURDAY LOOKS
LIKE A BETTER DAY FOR THUNDERSTORM ACTIVITY AS BETTER DYNAMICS GET
CLOSER TO THE AREA. SHOWERS AND THUNDERSTORMS STILL LOOK GOOD FOR
SUNDAY...BUT WITH SOMEWHAT COOLER TEMPERATURES...BELIEVE THAT IT WOULD
BE MORE SHOWERS THAN THUNDER THEN. MONDAY AND TUESDAY LOOK TO BE MORE
SHOWERY WITH COOLER AIR PRECLUDING THUNDERSTORMS. TUESDAY MIGHT
POSSIBLY CLEAR UP OVER THE WEST...BUT THAT WILL DEPEND ON WHERE THE
SURFACE TROUGH OVER THE DAKOTAS/POSSIBLY EASTERN MONTANA WILL ORIENT
ITSELF. DID SOME TINKERING WITH TEMPERATURES TO LINE UP GRIDWISE. CHB


    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 044 038/059 039/066 042/067 043/062 040/054 041/061
    9/R 83/T    33/T    34/T    44/T    44/W    43/W
LVM 047 033/059 036/062 038/065 040/059 036/053 034/060
    6/R 43/T    33/T    34/T    44/T    44/W    43/O
HDN 048 037/060 039/064 041/067 043/064 039/054 040/062
    +/R 83/T    32/T    23/T    34/T    44/W    43/W
MLS 052 037/063 038/073 041/070 042/064 042/054 041/058
    3/R 33/W    30/E    00/E    33/T    33/W    33/W
4BQ 044 034/058 037/066 041/068 041/061 042/054 039/053
    9/R 83/W    32/T    23/T    33/T    33/W    33/W
BHK 049 035/061 036/071 039/068 040/062 042/054 039/056
    3/R 33/W    30/E    00/E    33/T    33/W    33/W
SHR 044 034/054 037/062 039/065 041/062 037/050 038/053
    +/R +3/T    33/T    34/T    44/T    44/W    43/W


.BYZ...
MT...NONE.
WY...HEAVY SNOW WARNING FOR TODAY AND TONIGHT FOR ZONE WYZ098.

$$