Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 270311
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
911 PM MDT SUN JUL 26 2015

.DISCUSSION...
AS OF 8 PM THE MAIN INSTABILITY WAS OVER THE EASTERN PLAINS SO
DROPPED THE MENTION OF THUNDERSTORMS ELSEWHERE OVER THE FORECAST
AREA. FOR AFTER MIDNIGHT LATEST GUIDANCE DOES NOT SUPPORT A
MENTION OF THUNDERSTORMS OVER THE NW PLAINS SO DROPPED THEIR
MENTION IN THAT REGION. AS OF 9 PM ONE AREA OF THUNDERSTORMS WAS
NEAR AND E OF A LEWISTOWN-HAVRE LINE AND SHOULD MOVE OUT OF
EASTERN BLAINE AND EASTERN FERGUS COUNTIES AROUND 11 PM. SHOWERS
ARE EXPECTED TO INCREASE OVER SOUTHWEST MONTANA LATE TONIGHT THEN
SPREAD TO CENTRAL MONTANA BETWEEN 6 AM AND 9 AM. AS FOR SKY COVER
DID GO PARTLY CLOUDY OVER SE MADISON AND SOUTHERN GALLATIN FOR THE
REST OF THIS EVENING OTHERWISE WENT WITH MORE CLOUDY SKIES.
FORECAST LOWS LOOK OK BUT NOT SURE GREAT FALLS WILL GET TO A LOW
IN THE LOW 50S. HOWEVER DID NOT CHANGE THE FORECAST AS A FEW
GUIDANCE HAVE LOWS IN THAT RANGE. BLANK

&&

.AVIATION...
UPDATED 2345Z.

THUNDERSTORMS WILL AFFECT THE AREA NEAR AND EAST OF A LINE FROM KLWT-
KHVR THROUGH EARLY EVENING. EXPECT A PERIOD MVFR CONDITIONS IN HEAVY
RAIN AND WIND GUSTS AS HIGH AS 40 KTS. OTHERWISE EXPECT ISOLATED TO
SCATTERED SHOWERS AND A THUNDERSTORM OR TWO OVER THE REMAINDER OF
CENTRAL AND NORTHERN MONTANA THROUGH MIDNIGHT. LATE TONIGHT AND
MONDAY MORNING WIDESPREAD RAIN WILL DEVELOP WITH THE POSSIBLE
EXCEPTION OF THE FAR NW PLAINS. IT LOOKS LIKE WITHIN THIS RAIN MVFR
CEILINGS AND VISIBILITIES WILL BE THE RULE RATHER THAN THE EXCEPTION
AND LOCAL IFR CEILINGS ARE ALSO A THREAT. EXPECT WIDESPREAD MOUNTAIN
OBSCUREMENT. BLANK

&&

.PREV DISCUSSION...
/ISSUED 545 PM MDT SUN JUL 26 2015/

TONIGHT THROUGH TUESDAY...AN UPPER LEVEL LOW PRESSURE TROF OVER THE
WEST COAST WILL MOVE THROUGH THE PACIFIC NORTHWEST DURING THE
NIGHT. THE ASSOCIATED COLD FRONT WILL CROSS THE CWA TONIGHT AND
BRING WIDESPREAD PRECIPITATION ACROSS THE REGION AFTER MIDNIGHT.
MUCH COOLER/COLDER TEMPERATURES WILL FOLLOW ON MONDAY. THE LOW
PRESSURE TROF WILL CROSS SOUTHERN IDAHO MONDAY AND THE POSITION
WILL CREATE GOOD LIFT ACROSS MUCH OF THE CWA THROUGH THE DAY. THE
MID LEVEL CLOSED CIRCULATION CENTER WILL PASS OVER HAVRE MONDAY
AFTERNOON AND THE NORTHEASTERN ZONES SHOULD RECEIVE THE LARGEST
AMOUNTS OF RAIN IN OUR CWA. THE LOW PRESSURE CENTER WILL MOVE EAST
OF THE ZONES TUESDAY AND FLOW ALOFT WILL SWITCH TO THE NORTHWEST.
THE SURFACE PRESSURE GRADIENT WILL BECOME QUITE TIGHT, ESPECIALLY
ALONG THE EASTERN ZONES, AND BRISK, GUSTY CONDITIONS ARE EXPECTED
THROUGH THE DAY. TEMPERATURES BEHIND THE FRONT ON MONDAY WILL BE
25 TO 30 DEGREES BELOW NORMALS. TEMPERATURES WILL BEGIN TO RECOVER
TUESDAY BUT STILL REMAIN A GOOD 10 DEGREES BELOW NORMALS. ZELZER

TUESDAY NIGHT THROUGH SUNDAY...THE MEDIUM RANGE PERIOD BEGINS WITH A
CLOSED UPPER LOW AND ASSOCIATED TROF EXITING THE AREA TO THE EAST.
500MB HEIGHTS RISE ON WEDNESDAY AND THE FLOW ALOFT BECOMES WEST TO
NORTHWEST AND USHERS IN A QUIET WEATHER PATTERN. WARM AND DRY
CONDITIONS BEGIN WEDNESDAY AND CONTINUE THROUGH FRIDAY. WEAK SHORT
WAVE ENERGY WILL MOVE SOUTH OUT OF CANADA SATURDAY AND SUNDAY AND
BRING A SLIGHT CHANCE OF SHOWERS TO THE HI-LINE BOTH DAYS.
TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE SEASONAL AVERAGES
THROUGH THE PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  51  54  51  71 /  80  90  70  30
CTB  50  61  50  72 /  60  80  80  20
HLN  54  56  47  73 /  70  90  60  20
BZN  54  60  47  72 /  30  80  60  20
WEY  43  58  32  64 /  30  40  40  20
DLN  52  59  40  70 /  60  90  60  20
HVR  57  61  52  71 /  80 100 100  60
LWT  55  61  49  68 /  50  80  50  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

WEATHER.GOV/GREATFALLS



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