RSS FeedsIssued by NWS Cheyenne, WY
000 FXUS65 KCYS 251025 AFDCYS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 325 AM MST WED NOV 25 2009 .SHORT TERM...TODAY THROUGH THURSDAY NIGHT... A SHORTWAVE TROUGH WAS MOVING INTO THE NORTHERN PART OF THE CWA AS OF 09Z PER SATELLITE IMAGERY. THE FEATURE WILL CONTINUE TO MOVE RAPIDLY TO THE SOUTHEAST AND WILL EXIT THE EAST PART OF THE CWA BY 15Z. THE ASSOCIATED SHALLOW COLD FRONT AT THAT TIME WAS THROUGH ALL AREAS TO THE EAST OF THE LARAMIE RANGE. THE WEST EDGE OF THE BAROCLINIC CLOUD BAND EXTENDED FROM THE PANHANDLE TO KDGW EARLY THIS MORNING AND HAS BEEN MOVING QUICKLY SOUTHEAST AHEAD OF THE SHORTWAVE TROUGH. MANY PLACES TO THE NORTH OF A KDGW TO KAIA LINE RECEIVED LIGHT SNOW OR FLURRIES AS THE BAND MOVED OVERHEAD. IT APPEARS THAT THE SNOW LASTS FOR 2 TO 4 HOURS AND THE HISTORY HAS BEEN FOR A DUSTING OF NEW SNOW WITH VISIBILITIES REDUCED TO AS LOW AS A MILE FOR 1 TO 2 HOURS. THE LIGHT SNOW OR FLURRIES WILL AFFECT MUCH OF THE SOUTHERN PANHANDLE AND NEARBY PARTS OF SOUTHEAST WYOMING THROUGH 15Z OR SO AS THE CLOUD BAND MOVES SOUTHEAST. OTHERWISE...THE REMAINDER OF THIS PART OF THE FORECAST IS QUIET AS HEIGHTS ALOFT RISE LATER TODAY THROUGH 12Z FRIDAY. MODELS DEPICT THE RIDGE AXIS OVER THE CWA AT 12Z FRIDAY. THE SURFACE BOUNDARY WILL END UP ALONG THE LARAMIE RANGE TODAY AND THEN MOVE EAST AS A LOW PRESSURE TROUGH TONIGHT AND THURSDAY. TEMPERATURES WILL WARM SOME OVER THE WEST PART OF THE CWA AND WILL BE A BIT COOLER THAN TUESDAY OVER THE EAST PART OF THE CWA. TEMPERATURES FOR THURASDAY WILL BE ABOUT 10 DEGREES WARMER THAN THOSE OF TODAY ACROSS THE CWA. THERE WILL ALSO BE A MINIMUM OF CLOUD COVER THROUGH 12Z FRIDAY. THE ONLY ISSUE TO DEAL WITH WILL BE GUSTY WESTERLY SURFACE WINDS TO 40 MPH OVER AND NEAR THE LARAMIE AND SNOWY RANGES THROUGH THURSDAY NIGHT BEHIND THE SURFACE LOW PRESSURE TROUGH. .LONG TERM...FRIDAY THROUGH TUESDAY THE GFS AND ECMWF ARE FINALLY SIMILAR IN THE HANDLING OF THE UPPER TROUGH MOVING ACROSS THE AREA THIS WEEKEND. BASED MOST OF THE FORECAST FOR POPS AND TEMPS ON THE ECMWF. SW FLOW WILL BE ALOFT ON FRI AHEAD OF THE UPPER TROUGH HEADED TOWARDS THE CWA FROM THE WEST COAST. A THERMAL RIDGE OVER THE FORECAST AREA FRIDAY WILL RESULT IN VERY MILD CONDITIONS UNDER SUNNY SKIES. THE COLD FRONT ASSOCIATED WITH THE UPPER TROUGH WILL MOVE ACROSS THE CWA LATE FRIDAY NIGHT/EARLY SATURDAY MORNING. MUCH COLDER TEMPERATURES WILL OCCUR SATURDAY. THE UPPER TROUGH WILL BEGIN TO MOVE ACROSS WY ON SAT...AND WILL SPLIT WITH THE NORTHERN PORTION MOVING ACROSS THE NORTHERN PLAINS...AND THE SOUTHERN PORTION HOLDING BACK OVER AZ. WEAK ENERGY WILL BE LEFT OVER THE CWA...SO HAVE CUT POPS BACK A LITTLE BIT. A CHANCE OF LIGHT SNOW CAN BE EXPECTED ACROSS AREAS MAINLY IN AND NEAR THE LARAMIE RANGE AND TO THE WEST. NO SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED...NOT EVEN IN THE MOUNTAINS. SPOTTY AREAS OF LIGHT SNOW WILL CONTINUE ACROSS THE CWA SAT NIGHT...BUT AGAIN MOST PLACES WILL ONLY SEE A DUSTING. BY SUN...NORTH FLOW WILL OCCUR ALOFT AS AN UPPER RIDGE PUSHES INTO THE PAC NW AND THE NORTHERN UPPER TROUGH AXIS MOVES EAST. COLD TEMPERATURES WILL CONTINUE ON SUN. THE UPPER TROUGHS APPEAR TO MERGE BACK TOGETHER ON MON WITH THE AXIS EXTENDING FROM NORTHERN MICHIGAN...ACROSS IL...ALL THE WAY BACK TO THE BAJA PENINSULA BY 00Z TUES. THE UPPER RIDGE WILL MOVE OVER THE CWA DURING THE DAY MON AS A SHORT WAVE MOVES INTO THE PAC NW. TEMPERATURES WILL MODERATE A BIT ON MON ACROSS THE FORECAST AREA WITH BRISK WINDS AT THE SURFACE. ON TUES...THE UPPER TROUGH OVER THE PAC NW CONTINUES TO MOVE EAST AS THE UPPER RIDGE MOVES OFF TO THE EAST. THE UPPER TROUGH WILL DEEPEN SIGNIFICANTLY ON TUES...RESULTING IN A LARGE, BROAD UPPER TROUGH OVER THE WESTERN U.S. BY 12Z WED. AT SURFACE OVER THE FORECAST AREA...A LEE TROUGH WILL SET UP SO WINDY CONDITIONS CAN BE EXPECTED TUES DURING THE DAY. THE COLD FRONT ASSOCIATED WITH THIS NEXT UPPER TROUGH WILL MOVE ACROSS THE CWA BY MID EVENING BRINGING A CHANCE OF SNOW AND COLDER TEMPERATURES TO THE AREA. HIGH TEMPERATURES WILL BE FROM 10 TO 15 DEGREES ABOVE NORMAL FRIDAY...AROUND NORMAL SAT...4 TO 8 DEGREES BELOW NORMAL SUN AND MON...AND AROUND NORMAL ON TUES. && .AVIATION...AN AREA OF MVFR CEILINGS AND VISIBILITIES IN LIGHT SNOW WILL CONTINUE TO SPREAD SOUTHEAST OVER THE EAST PART OF THE CWA THROUGH MID MORNING. SOME AIRPORTS THAT WILL BE AFFECTED BY THE MVFR CONDITIONS WILL BE KBFF...KSNY...KTOR AND KIBM. VFR CONDITIONS WILL THEN BE OVER THE ENTIRE CWA BY LATE MORNING AND CONTINUE THROUGH THURSDAY NIGHT. NORTHERLY SURFACE WINDS WILL GUST AS HIGH AS 30 KNOTS TO THE EAST OF THE LARAMIE RANGE TODAY. WESTERLY SURFACE WINDS WILL GUST AS HIGH AS 35 KNOTS IN AREAS OVER AND WEST OF THE LARAMIE RANGE THROUGH 12Z FRIDAY. && .FIRE WEATHER...NO FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE MID PART OF NEXT WEEK. HOWEVER ON FRIDAY...AREAS JUST TO THE EAST OF THE LARAMIE RANGE WILL EXPERIENCE THE COMBINATION OF ABOVE NORMAL TEMPERATURES...MINIMUM RELATIVE HUMIDITIES OF AROUND 25 PERCENT AND WESTERLY WINDS GUSTING TO 40 MPH. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ WEILAND/KMD
