Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 281746
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1146 AM MDT SAT MAR 28 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM MDT SAT MAR 28 2015

SATELLITE PIX EARLY THIS MORNING SHOW A WELL-DEFINED SHORTWAVE
SPINNING INTO THE PACNW WITH SFC OBS SITES DEPICTING ITS ASSOCIATED
SFC REFLECTED PACIFIC FRONT ALREADY THRU MUCH OF WASHINGTON AND
OREGON. THIS DISTURBANCE WILL BE THE CATALYST FOR THE FIRE WEATHER
CONCERNS TODAY ALONG WITH THE POSSIBILITY OF A FEW WEAK SHOWERS
THIS EVENING. 00Z MODELS ARE CONSISTENT IN TRACKING THIS SHORTWAVE
ENERGY FROM THE PACNW THIS MORNING THRU MONTANA TODAY AND INTO THE
NRN PLAINS TONIGHT. AS IT DOES SO IT WILL DRIVE A FRONT THRU THIS
EVENING. LLVL THERMAL RIDGE WILL AMPLIFY IN THE WARM SECTOR TODAY
BOOSTING HIGH TEMPERATURES TO RECORD LEVELS IN SPOTS. LITTLE OR NO
UPSTREAM CLOUD COVER SUGGESTS DEEP MIXING WHICH WILL INDUCE BREEZY
TO LOCALLY WINDY WEST WINDS BY LATE THIS MORNING AND THIS
AFTERNOON. ADIABATIC WARMING/DRYING IN THE LEE WILL MAGNIFY THE
PLUMMETING AFTERNOON HUMIDITIES. HUMIDITIES WILL FALL WELL BELOW
CRITICAL THRESHOLDS TODAY AND WHEN COMBINED WITH THE BREEZY
CONDITIONS AND PRE-GREENUP FUELS WILL SET THE STAGE FOR A CRITICAL
FIRE WEATHER DAY. MODELS DO SQUEEZE OUT SOME WEAK SHOWER ACTIVITY
ALONG THE FRONT LATE THIS AFTERNOON OVR THE MOUNTAINS...PERHAPS
SPREADING OUT ONTO THE ERN PLAINS THIS EVENING. THE DRY LLVLS WILL
BE DIFFICULT TO OVERCOME BUT GIVEN THE PROXIMITY OF THE SHORTWAVE
ALONG WITH THE FRONT...ITS HARD TO COMPLETELY RULE OUT AT LEAST THE
POSSIBILITY. HOWEVER...MOST PLACES WILL REMAIN DRY.

THIS SYSTEM WILL REACH THE UPPER MISSISSIPPI RIVER VALLEY SUNDAY
LEAVING COOLER TEMPERATURES ALONG WITH BREEZY NORTHWEST WINDS OVR
THE NEBRASKA PANHANDLE. EVEN SO...HIGH TEMPERATURES ON SUNDAY WILL
REACH UPPER 50S WEST/LOW 60S EAST. NORTHWEST FLOW WILL CONTINUE
ON MONDAY AS THE NEXT UPSTREAM RIDGE APPROACHES THE INTERMOUNTAIN
WEST. THE EFFECTS OF THIS AFTERNOONS COLD FROPA WILL BE LONG GONE
BY MONDAY...WITH LLVL WAA UNDERWAY. MONDAY WILL FEATURE ANOTHER
DRY DAY WITH HIGHS RETURNING TO THE 60S OVR SE WYOMING WITH LOW
70S OVR THE WRN NEBRASKA PANHANDLE.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 345 AM MDT SAT MAR 28 2015

WARMEST DAY OF THE WEEK LIKELY WILL BE TUESDAY AS AN UPPER RIDGE
PASSES ACROSS THE REGION WITH LEE TROUGHING SETTING UP A WARM AND
DRY DOWNSLOPE PATTERN OVER MUCH OF THE CWA. THERMAL RIDGE MOVES
ACROSS THE AREA LATE TUESDAY WITH 700MB TEMPS FROM 4 TO 6C.
PACIFIC FRONT WILL THEN MOVE EAST ACROSS THE CWA LATER TUESDAY
NIGHT WITH BREEZY AND COOLER CONDITIONS WEDS. LITTLE IF ANY PCPN
ASSOCIATED WITH THE FRONT. EVEN COOLER CONDITIONS EXPECTED TO
CLOSE OUT THE WEEK AS AN UPPER TROUGH MOVES ONSHORE OVER THE
PACIFIC NW LATE WEDS AND PROGRESSES EASTWARD THURSDAY...PASSING
ACROSS THE CWA THURSDAY NIGHT. NEXT PUSH OF COOLER AIR ARRIVES
THURSDAY AHEAD OF THE UPPER TROUGH WITH THE BEST CHANCE FOR PCPN
EXPECTED LATE THURSDAY AND THURSDAY NIGHT AS A PERIOD OF UPSLOPE
FLOW OCCURS BEHIND THE FRONT. DRYING OUT FRIDAY WITH MILD TEMPS
THOUGH A BIT BREEZY OVER THE PLAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1140 AM MDT SAT MAR 28 2015

VFR CONDITIONS THROUGH THE TAF PERIOD. IT WILL BE BREEZY TO WINDY
ACROSS THE REGION THROUGH THE AFTERNOON. WEST WIND GUSTS TO 30-35
KTS ARE EXPECTED ACROSS SOUTHEAST WY WITH 20-25 KTS OVER THE
NEBRASKA PANHANDLE. A COLD FRONT WILL PASS OVER THE SITES THIS
EVENING AND EARLY TONIGHT WITH WINDS BECOMING NORTHWEST TO THE
EAST OF THE LARAMIE RANGE. GUSTS TO 25-30 KTS WILL BE POSSIBLE
THROUGH SUN MORNING BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 345 AM MDT SAT MAR 28 2015

RED FLAG CONDITIONS A CERTAINTY EAST OF THE MOUNTAINS TODAY AS A
VERY DRY AIR MASS COMBINES WITH WINDS KICKED UP BY AN APPROACHING
DISTURBANCE. WIND GUSTS OF 30 TO 45 MPH ARE EXPECTED ALONG WITH
HUMIDITIES THAT WILL AT A MINIMUM DROP INTO THE LOW TEENS. A FEW
PLACES ALONG THE I25 CORRIDOR MAY EVEN SEE UPPER SINGLE DIGITS FOR
HUMIDITIES. A COLD FRONT WILL PASS THRU THE DISTRICT EARLY THIS
EVENING TURNING WINDS FROM WEST TO NORTHWEST AND PRODUCING THE
POTENTIAL FOR ISOLATED AND VERY WEAK SHOWER ACTIVITY. IF THESE
SHOWERS DO DEVELOP...WOULD EXPECT ERRATIC WIND DIRECTIONS IN THEIR
VICINITY. LITTLE OR NO PRECIPITATION WILL ACCOMPANY THIS ACTIVITY.
CONDITIONS WILL IMPROVE DRAMATICALLY BY SUNSET TONIGHT. FIRE
WEATHER CONDITIONS WILL BE ELEVATED AGAIN ON SUNDAY...THOUGH
HUMIDITIES ARE ONLY EXPECTED TO BOTTOM OUT IN THE UPPER TEENS. DRY
CONDITIONS WILL CONTINUE INTO MONDAY AS WELL. WINDS ON MONDAY WILL
DECREASE EAST OF THE LARAMIE RANGE...YET INCREASE OVR
CARBON/ALBANY COUNTIES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ301-310.

NE...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR NEZ311>313.

&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...ZF
FIRE WEATHER...CAH



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