FXUS65 KTFX 261801 AAA
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 AM MST SAT DEC 26 2009
UPDATE AVIATION SECTION...
.UPDATE...
CURRENT FORECAST IS ON TRACK...WITH JUST A FEW MINOR ADJUSTMENTS.
FAIRLY QUIET WEATHER WITH MOSTLY CLEAR SKIES CURRENTLY RESIDES
OVER THE REGION. WITH THE CLEAR SKIES...PATCHY FREEZING FOG
CONTINUES TO AFFECT PORTIONS OF THE REGION...INCLUDING
BOZEMAN...HELENA AND HAVRE. THE FOG SHOULD GENERALLY BEGIN TO
DISSIPATE BY MID AFTERNOON. OTHERWISE...QUIET WEATHER EXPECTED
OVER THE REGION. A FEW ADJUSTMENTS MADE TO TEMPERATURES...BUT
OVERALL GENERALLY SEASONABLE DECEMBER LIKE TEMPERATURES EXPECTED
OVER THE REGION FOR TODAY. BRUSDA
&&
.AVIATION...
AFTER A BOUT WITH FOG THIS MORNING AT KBZN...KHLN AND KHVR...AND IN
THE MILK RIVER VALLEY AND NORTHERN CHOUTEAU COUNTY...EXPECT
CONDITIONS TO IMPROVE TO VFR ACROSS THE AREA. WITH LIGHT WINDS AND
COLD TEMPERATURES...EXPECT FOG TO FORM AGAIN OVERNIGHT AT THE
PREVIOUSLY MENTIONED TERMINALS AND LOCATIONS. ELSEWHERE EXPECT VFR
CONDITIONS. DB
&&
.PREV DISCUSSION...
/ISSUED 339 AM MST SAT DEC 26 2009/
SATURDAY THROUGH TUESDAY...AN UPPER LEVEL HIGH PRESSURE RIDGE
OVER THE PACIFIC NORTHWEST WILL MOVE SLOWLY EAST AND WEAK NORTH
FLOW OVER THE ZONES WILL BECOME EASTERLY DURING THE DAY. A
BOUNDARY WILL BE ACROSS NORTH CENTRAL MONTANA...BETWEEN KHVR AND
KCTB...WITH THE COOLER AIR TO THE EAST. THE WEAK HIGH PRESSURE
RIDGE WILL SIT ACROSS THE AREA SATURDAY NIGHT AND THE AIRMASS
WILL CONTINUE TO WARM SLOWLY...AND WARMER BOUNDARY LAYER TEMPS
SHOULD FINALLY SPREAD ACROSS THE EASTERN ZONES. THE HIGH PRESSURE
RIDGE WILL SLOWLY MOVES EAST AND BY SUNDAY NIGHT A LOW PRESSURE
TROF WILL MOVE OVER THE WEST COAST. THE ZONES WILL THEN COME
UNDER WEAK SOUTHERLY FLOW AHEAD OF THIS SYSTEM. BY TUESDAY
MORNING...THE UPPER LEVEL TROF MOVES OVER THE ROCKIES.
DYNAMICS...AT THIS POINT...APPEAR RATHER WEAK AND WILL MAINLY
AFFECT THE NORTHERN ROCKIES. MOISTURE AHEAD OF THIS SYSTEM WILL
SPREAD ACROSS THE ROCKIES AND OVER THE ZONES LATE MONDAY NIGHT
AND TUESDAY. MOISTURE WILL MAINLY BE AT MID-LEVELS AND MOST
PRECIP WILL BE RESTRICTED TO THE ROCKIES. TEMPS WILL SLOWLY RISE
DURING THE PERIOD...AND WITH THE AID OF INCREASE WEST SURFACE
FLOW SUNDAY AND MONDAY...MOST OF THE PLAINS WILL RISE TO NEAR OR
SLIGHTLY BELOW NORMALS. TEMPS ACROSS SOUTHWEST MONTANA WILL ALSO
RISE BUT GENERALLY REMAIN BELOW NORMALS. ZELZER
TUESDAY NIGHT THROUGH SATURDAY...NORTHWEST FLOW ALOFT WILL KEEP
CONDITIONS DRY AND COOL THROUGH WEDNESDAY. NEXT SHORTWAVE TROUGH
MOVES INTO THE CWA OVERNIGHT WEDNESDAY AND THURSDAY. MODELS ARE
SOMEWHAT CONSISTENT WITH THE TIMING AND LOCATION. SLIGHTLY
INCREASED POPS THROUGH THURSDAY AND KEPT TEMPS BELOW SEASONAL
AVERAGES. MODELS CONTINUE TO DIVERGE IN TREND FOR THE NEW YEAR
WEEKEND. LATEST EC INDICATES A BUILDING RIDGE OF HIGH PRESSURE AND
ABOVE AVERAGE TEMPERATURES THROUGH THE END OF THE FORECAST PERIOD
WHILE THE GFS BRINGS A SHORT WAVE OVER THE AREA WITH COLDER
TEMPERATURES OVER THE REGION. LEANING ON THE GFS SOLUTION AND KEPT
TEMPERATURES JUST BELOW SEASONAL AVERAGES AND KEPT POPS NEAR
CLIMATOLOGY. MERCER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 30 8 31 16 / 0 0 0 0
CTB 22 12 34 12 / 0 0 0 0
HLN 17 3 22 2 / 0 0 0 0
BZN 22 -1 22 -2 / 0 0 0 0
WEY 12 -4 23 -3 / 0 0 0 10
DLN 21 2 24 5 / 0 0 0 0
HVR 15 -7 19 0 / 0 0 0 0
LWT 25 8 31 10 / 0 0 0 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
