Lightning Strike in Montana, July 26, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
906 PM MDT TUE JUL 25 2006

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
UPDATE TO AFP AND ZFP.

ISOLATED STORMS HAVE BEEN MAKING HEADWAY ACROSS CENTRAL AREAS OF
THE STATE THIS EVENING AND PROBABLY WILL STAY ALIVE FOR A FEW MORE
HOURS THANKS TO A DEVELOPING LOW LEVEL JET FROM THE SOUTH OVER
EASTERN MONTANA TONIGHT. HAVE INCREASED POPS OVER THE WESTERN AND
SOUTHERN ZONES ACCORDINGLY. ALSO WITH LOW LEVEL JET...EXPECT
RELATIVE HUMIDITIES TO STAY LOW ESPECIALLY IN THE CMR WILDLIFE
RESERVE. ADJUSTED THEM DOWN AS WELL. REST OF FORECAST LOOKS GOOD.

PREVIOUS DISCUSSION...
ONLY MINOR CHANGES IN THE LARGE-SCALE PATTERN. WHILE THE STRONG
UPPER HIGH CENTER HAS NOW MOVED FURTHER SOUTH TO THE SW
STATES...IT HAS LEFT BEHIND A WIDESPREAD AREA OF HEAT THROUGHOUT
MOST OF THE INLAND WEST. SO...DESPITE A SLIGHT DROP IN 500 MB
HEIGHTS...THICKNESSES HAVENT CHANGED MUCH...NOR WILL THEY THE
NEXT 2 DAYS. THEREFORE THE HOT SPELL CONTINUES. MOS TEMPS LOOK
PRETTY GOOD...BUT SLIGHT COOL BIAS LATELY. FWC WAY TOO COOL.

MEANWHILE...A SERIES OF SHORTWAVES HAVE BEEN ROTATING AROUND THE
UPPER HIGH...BUT A SLIGHT CHANGE HAS TAKEN PLACE IN THAT
SCENARIO...AS THE SUBTROPICAL MOISTURE HAS BEEN CUT OFF FROM OUR
AREA. INTERESTING THAT SURFACE DEW POINTS HAVE TENDED TO RISE...
WHILE THE MOISTURE ALOFT IS WANING BECAUSE LOW LEVEL AIR MASSES
FROM CANADA ARRIVING HAVE BEEN MOISTER THAN USUAL.

THERE IS A WEAK AND WEAKENING SHORTWAVE CURRENTLY MOVING ACROSS
OUR AREA. THIS IS MARKED ONLY BY A WEAK SURFACE COOL FRONT MOVING
SOUTH ACROSS THE CWA ACCOMPANIED ONLY BY SCATTERED CUMULUS.
ANOTHER STRONGER SHORTWAVE FROM THE WEST WITH PACIFIC MOISTURE
WILL MOVE ACROSS THE AREA LATE TONIGHT AND WEDNESDAY. THE AIRMASS
WILL BE UNSTABLE AND MOIST ENOUGH FOR ISOLATED THUNDERSTORMS
AGAIN...BUT AGAIN NOT MUCH MOISTURE EXPECTED. WRF CONTINUES TO BE
MUCH TOO WET. LITTLE CHANGE THURSDAY...IT APPEARS THE TREND TOWARD
EVEN WEAKER SHORTWAVES WILL CONTINUE...SO WILL HAVE NO POPS DURING
THE DAY. SIMONSEN

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
NO UPDATES. MODELS CONTINUE TO SHOW SAME SOLUTIONS AND TENDENCIES
AS DISCUSSED BY PREVIOUS SHIFT...AND HAVE SAME RESERVATIONS ABOUT
MAKING ANY CHANGES TO FORECAST. AGREE PERSISTENCE BEST APPROACH
FOR DEALING WITH WESTERN CONUS MEGA-RIDGE UNTIL SEE DEFINITIVE
SIGNS OF A PATTERN CHANGE.

PREVIOUS LONG TERM...
THE HOT AND MAINLY DRY PATTERN OF LATE TO CONTINUE.  A STRONG
SUB-TROPICAL RIDGE TO REMAIN FIRMLY ANCHORED ACROSS THE SOUTHWEST
UNITED STATES.  HEIGHTS AND THICKNESS VALUES WILL STILL BE ABOVE
AVERAGE...AND SO TOO THE TEMPERATURES. MODELS IN GOOD AGREEMENT
THAT BY EARLY NEXT WEEK THAT A GULF OF ALASKA LOW DROPS SOUTH TO
OFF THE PACIFIC NORTHWEST COAST. OPERATIONAL GFS TRIES TO SWING
THE UPPER TROUGH ACROSS MONTANA BY TUESDAY...BUT MANY OF THE
ENSEMBLES AND THE ECMWF KEEP THE UPPER TROUGH AT BAY. GIVEN THE
HOT/MAINLY DRY SUMMER PREFER KEEPING THINGS DRY AND HOT UNTIL
THERE ARE VERY CLEAR INDICATIONS THAT THE PATTERN WILL CHANGE.
SOUTHWEST FLOW ALOFT IS NOT ENOUGH THIS FAR OUT FOR A BROADBRUSH
POPS FOR THIS WEEKEND INTO EARLY NEXT WEEK.

THURS NIGHT & FRIDAY...THE EXTENDED PERIOD STARTS WITH AN UPPER
RIDGE CENTERED IN THE CENTRAL GREAT BASIN/SOUTHWESTERN UNITED
STATES.  AN UPPER TROUGH WILL BE DROPPING SOUTH ALONG THE BRITISH
COLUMBIA COAST.  HEIGHTS AND 1000-500MB THICKNESS VALUES REMAIN
LITTLE CHANGED FROM LATE...AND TEMPERATURES WILL CONTINUE TO BE
ABOVE AVERAGE WITH HIGHS MOSTLY IN THE 90S.

NEXT WEEKEND...THE UPPER LOW DROPS SOUTH INTO SOUTHERN BRITISH
COLUMBIA AND INTO THE PACIFIC NORTHWEST.  THIS WILL CAUSE THE
SUB-TROPICAL RIDGE TO SHIFT EAST AND AMPLIFY ACROSS THE PLAINS.  AS
THE UPPER FLOW GRADUALLY BECOMES MORE SOUTHWEST IT DOES OPEN THE
DOOR BY LATER SUNDAY FOR SHORTWAVE ENERGY TO RIDE NORTHEAST TOWARD
THE CWA.  IF ANY OF THE WAVES CAN TAP OR PULL UP SOME MONSOONAL
MOISTURE IT COULD LEAD TO ISOLATED STORMS.  THIS FAR OUT THOU
CONFIDENCE IS NOT GREAT ENOUGH TO ADVERTISE ANY RAIN.  WOULD MUCH
PREFER TO HOLD THE COURSE AND WAIT UNTIL THERE IS SOMETHING THAT CAN
BE SEEN.  IT ALSO LOOKS LIKE THERE WILL BE A WARM FRONT LATE FRIDAY
NIGHT OR SATURDAY MORNING LIFTING THROUGH SOUTH DAKOTA THAT MAY
TOUCH OFF SOME CONVECTION TO THE SOUTH AND EAST OF THE CWA.  BUMPED
UP THE CLOUD COVER SOME FROM 06-18Z SATURDAY ACROSS MY SOUTHEAST
ZONES...BUT KEPT IT DRY.  THE OTHER ISSUE IS THE HEAT.  AS THE RIDGE
AMPLIFIES ACROSS THE AREA IT SHOULD PULL SOME MIGHTY TOASTY AIR UP
INTO EASTERN MONTANA...AND WOULD NOT BE AT ALL SURPRISED TO SEE
SOME TRIPLE DIGIT HEAT BY SUNDAY. THE BIGGEST CHANGE DURING THIS
TIME WILL BE TO BOOST TEMPERATURES A COUPLE OF DEGREES SATURDAY
AND SEVERAL DEGREES SUNDAY.

FIRST HALF OF NEXT WEEK...SOME UNCERTAINTY AS TO WHAT WILL HAPPEN
WITH THE UPPER AIR PATTERN...AND THUS PREFER TO TOE THE PERSISTENCE
LINE FOR NOW.  OPERATIONAL GFS SHIFTS THE SUB-TROPICAL HIGH INTO THE
OHIO VALLEY BY THE MIDDLE OF THE WEEK ALLOWING THE PACIFIC TROUGH TO
MAKE SOME INROADS INTO THE INTERMOUNTAIN WEST WITH A COOLER AND
UNSETTLED PATTERN.  SO FAR THIS SUMMER THE OPERATIONAL GFS HAS ON
SEVERAL OCCASIONS WANTED TO BREAK DOWN THE RIDGE AND HAS TURNED OUT
MUCH TOO PROGRESSIVE OR COMPLETELY OUT TO LUNCH.  GIVEN THAT WE ARE
AT THE CLIMATOLOGICAL PEAK OF SUMMER PREFER TO SIDE THE WAY OF
MANY OF THE ENSEMBLE MEMBERS THAT MAINTAIN A STRONG RIDGE ACROSS
THE NORTHERN PLAINS WITH ABOVE NORMAL TEMPERATURES. IT IS ALSO
VERY DIFFICULT TO BREAK DOWN A STRONG RIDGE THIS TIME OF
YEAR...AND HARD TO BEAT PERSISTENCE GIVEN A LONG PERIOD OF ABOVE
NORMAL TEMPERATURES AND VERY DRY WEATHER THIS SUMMER. CB

&&

.AVIATION...
VFR WILL PREVAIL. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL
BE POSSIBLE AFTER MIDNIGHT THROUGH WEDNESDAY ACROSS THE REGION...
BUT CLOUD BASES ARE EXPECTED TO BE AOA 12K FT AGL WITH LITTLE IF ANY
RAINFALL TO REDUCE VISIBILITY. NORTHEAST WIND WILL BECOME MORE EASTERLY
OVERNIGHT BEFORE SHIFTING WEST BY WEDNESDAY AFTERNOON. WIND SPEEDS
GENERALLY LESS THAN 15 KTS EXCEPT LOCALLY VARIABLE AND GUSTY NEAR
ANY THUNDERSTORMS.

&&

.FIRE WEATHER...
HOT WEATHER CONTINUES THROUGH THE NEXT FEW DAYS ALTHOUGH DEW
POINTS IN THE 40S AND 50S WILL ALLOW FOR MODERATE OVERNIGHT
RELATIVE HUMIDITY RECOVERY. AN UPPER WEATHER FEATURE MOVING ALONG
THE CANADIAN BORDER WILL PUSH A FRONT ACROSS THE REGION ON
WEDNESDAY WITH A WIND SHIFT AND SLIGHTLY STRONGER WINDS EXPECTED.
THUNDERSTORMS ARE ALSO POSSIBLE WITH THIS WEATHER SYSTEM ALTHOUGH
THE BEST CHANCE WILL BE ACROSS THE NORTH. A BIT OF RELIEF FROM THE
HEAT EXPECTED THURSDAY AS NORTH WINDS BEHIND THE FRONT PULL COOLER
AIR SOUTH OF THE BORDER. NORTHERN ZONES WILL HAVE THE MOST BENEFIT
WITH HIGH TEMPERATURES CLOSER TO 90 THAN 100. RAE

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

WEATHER.GOV/GLASGOW