Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 042349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT TUE AUG 4 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 245 PM MDT TUE AUG 4 2015

CURRENT WATER VAPOR SATELLITE LOOP SHOWS THE UPPER LEVEL LOW
PUSHING INTO WESTERN NEBRASKA AT THIS HOUR. A FEW MODELS WERE
MUCH TOO DRY FOR TODAY...ALTHOUGH WESTERLY WINDS DID GUST UP TO
40 MPH THIS AFTERNOON. EVEN WITH THE WESTERLY FLOW...DEWPOINTS
REMAIN IN THE UPPER 40S TO AROUND 50 DEGREES ACROSS SOUTHEAST
WYOMING. THUNDERSTORMS HAVE REDEVELOPED OVER EAST CENTRAL WYOMING
AND WESTERN NEBRASKA THIS AFTERNOON DUE TO SOME COOLER AIR ALOFT
PUSHING OVER THE AREA. DO NOT EXPECT SEVERE THUNDERSTORMS AT THIS
TIME...ALTHOUGH SOME MAY BECOME STRONG WITH SMALL HAIL...GUSTY
WINDS...AND HEAVY RAINFALL. KEPT NUMEROUS WORDING NORTH OF A
DOUGLAS TO ALLIANCE LINE INTO THIS EVENING WITH SCATTERED TO
ISOLATED WORDING AS YOU GO FURTHER SOUTH AND WEST. ALTHOUGH
CONDITIONS ARE NOT TOO BAD RIGHT NOW ALONG THE I80
CORRIDOR...MODELS INDICATE ANOTHER ROUND OF SHOWERS AND TSTORMS
ACROSS ALBANY AND LARAMIE COUNTIES LATE THIS AFTERNOON AND EARLY
THIS EVENING...SO KEPT POP BETWEEN 20 TO 35 PERCENT IN THOSE AREAS.

THE UPPER LEVEL FEATURE WILL QUICKLY MOVE EAST TONIGHT INTO THE
CENTRAL PLAINS WITH DRIER AIR BEGINNING TO MOVE INTO THE AREA. THE
ONLY EXCEPTION WILL BE THE NEBRASKA PANHANDLE WHERE SOME PATCHY
FOG IS POSSIBLE DUE TO LLVL MOISTURE AND LIGHT/VARIABLE WINDS. FOR
WEDNESDAY...MODELS SHOW THE UPPER LEVEL RIDGE AXIS REBUILDING OVER
THE ROCKY MOUNTAIN REGION. THE RIDGE AXIS IS RELATIVELY WEAK...AS
ANOTHER DISTURBANCE ALOFT QUICKLY MOVES INTO WYOMING BY WEDNESDAY
EVENING. CAN NOT RULE OUT ANOTHER ROUND OF SCATTERED SHOWERS AND
TSTORMS IN THE AFTERNOON AND EVENING HOURS ACROSS MUCH OF THE
AREA. HOWEVER...EXPECT TSTORM ACTIVITY TO BE RELATIVELY WEAK DUE
TO WARMER AIR ALOFT. TEMPERATURES WILL INCREASE BACK INTO THE MID
80S TO LOW 90S. THURSDAY WILL BE DRY AND MOSTLY CLEAR...WITH NO
TSTORM ACTIVITY ANTICIPATED AT THIS TIME. HIGH TEMPERATURES WILL
BE SIMILAR TO WEDNESDAY AND IN THE 80S TO LOW 90S.

.LONG TERM...(FRIDAY THROUGH TUESDAY)

MEDIUM RANGE MODELS CONTINUE TO ADVERTISE A FAIRLY STRONG MID LEVEL
SHORTWAVE LIFTING NORTHEAST ACROSS THE GREAT BASIN ON FRI. IT STILL
LOOKS LIKE THE BEST DYNAMICS WILL PASS TO THE NORTH OF THE CWA WITH
THE STRONGEST H25 JET ENERGY ALONG THE WY/MT BORDER. HOWEVER...THE
GFS SHOWS A MID LEVEL VORT MAX TRACKING ALONG THE I-80 CORRIDOR AT
00Z SAT...WHICH COMBINED WITH LLVL CONVERGENCE COULD PROVIDE ENOUGH
SUPPORT FOR AT LEAST ISOLATED CONVECTION BETWEEN CYS-SNY. GREATEST
PROBABILITIES FOR MORE WIDESPREAD SHOWERS/TSTMS SHOULD BE SATURDAY
AND SATURDAY NIGHT WITHIN MOIST SOUTHWEST FLOW ALOFT. DO NOT EXPECT
MUCH FOR SEVERE WEATHER AS BOTH THE ECMWF/GFS SHOW THE HIGHEST CAPE
TO OUR EAST OVER CENTRAL NE ALONG WITH MODEST SHEAR BENEATH 30 KTS
OF H5 FLOW. WARMEST TEMPERATURES OF THE PERIOD SHOULD COME LATE IN
THE WEEKEND INTO EARLY NEXT WEEK WITH RIDGING ALOFT...BUT GENERALLY
EXPECT NORMAL CONDITIONS FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 540 PM MDT TUE AUG 4 2015

ISOLATED RAIN SHOWERS WILL BE POSSIBLE OVER PORTIONS OF THE
NEBRASKA PANHANDLE THROUGH AROUND 03Z. WEST TO NORTHWEST WINDS
WILL OCCASIONALLY GUST TO 25-30 KTS THROUGH SUNSET ACROSS
SOUTHEAST WY BEFORE DECREASING. WITH WEAK WINDS AND A MOIST
AIRMASS NEAR THE SURFACE...PATCHY FOG COULD DEVELOP OVER THE
PANHANDLE BY LATE TONIGHT...HOWEVER CONFIDENCE IS NOT HIGH ENOUGH
AT THIS POINT TO INCLUDE AS A PREVAILING CONDITION.

&&

.FIRE WEATHER...
ISSUED AT 158 PM MDT TUE AUG 4 2015

THERE ARE SOME FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS DUE TO
SOME DRIER AIR MOVING INTO SOUTHEAST WYOMING...BUT CONCERNS WILL
BECOME MINIMAL BY THIS WEEKEND. SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS EVENING BEFORE A DRIER AND MORE STABLE AIRMASS MOVES
INTO THE REGION TONIGHT AND WEDNESDAY. RELATIVE HUMIDITIES WILL
TREND LOWER DURING THE MIDDLE PART OF THE WEEK WITH VALUES RANGING
BETWEEN 15 TO 25 PERCENT BY THURSDAY. THUNDERSTORMS WILL RETURN TO
THE AREA LATE THIS WEEK AND THIS WEEKEND AS SOME MONSOON MOISTURE
MOVES INTO THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...TJT
LONG TERM...CLH
AVIATION...ZF
FIRE WEATHER...TJT



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