Issued by NWS Pueblo, CO
000 FXUS65 KPUB 092212 AFDPUB AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 312 PM MST TUE FEB 9 2010 .SHORT TERM... (TONIGHT AND WEDNESDAY) CURRENTLY...WEAK SOUTHWESTERLY FLOW JUST ABOVE THE BOUNDARY LAYER ALLOWED MOST OF THE EASTERN PLAINS TO CLEAR BY LATE MORNING...THOUGH STRATUS/FOG/FLURRIES HAVE REDEVELOPED THIS AFTERNOON OVER EL PASO COUNTY...AS LIFT FROM SOUTHERLY BOUNDARY LAYER FLOW HAS BEEN STRONG ENOUGH SATURATE THE NEAR SURFACE AIR MASS. AREA OF STRATUS ALONG THE NM BORDER ALSO BEGINNING TO CREEP BACK NORTHWARD THIS AFTERNOON...WITH LOWER CLOUDS COVERING MUCH OF BACA COUNTY AT 22Z. OVER THE MOUNTAINS...PATCHY LOW AND MID LEVEL CLOUDINESS PERSISTS...WITH A FEW FLURRIES/-SHSN NOTED...MAINLY OVER THE SAN JUANS. TONIGHT...EXPECT STRATUS AND FOG TO RETURN TO MOST OF THE EASTERN PLAINS THIS EVENING...AS WEAK EASTERLY SURFACE WINDS AND SNOW COVER ALLOW AIR MASS TO COOL AND SATURATE FAIRLY QUICKLY AFTER SUNSET. MAY ALSO SEE A FEW FLURRIES THIS EVENING OVER THE EASTERN MOUNTAINS AND ACROSS EL PASO COUNTY...WHERE UPSLOPE COMPONENT IS STRONGEST. MODELS SUGGEST AREAS ADJACENT TO THE MOUNTAINS/WEST OF I-25 COULD CLEAR AFTER 06Z AS WESTERLY FLOW DEEPENS...THOUGH MOST OF THE LOWER ARKANSAS VALLEY WILL REMAIN SOCKED IN THROUGH SUNRISE. FARTHER WEST...SAN LUIS VALLEY WAS SLOW TO BREAK THE INVERSION TODAY...AND SUSPECT STRATUS/FOG WILL REDEVELOP HERE AS WELL. OVER THE MOUNTAINS...ENOUGH MOISTURE SHOULD LINGER TO PRODUCE AT LEAST SPOTTY SNOW SHOWERS/FLURRIES...THOUGH SNOW AMOUNTS WILL BE LIGHT. LOW TEMPS PROBLEMATIC WITH STRATUS/FOG AROUND...WHILE CURRENT VERY LOW DEW POINTS SUGGEST FAR SOUTHEAST PLAINS COULD GET FAIRLY COLD QUICKLY THIS EVENING BEFORE FOG DEVELOPS. IN GENERAL...GIVEN CURRENT COLDER THAN GUIDANCE TEMPS AND LOW DEW POINTS...UNDERCUT MOS NUMBERS A FEW DEGREES MANY AREAS. WEDNESDAY...LOW LEVEL FLOW BECOMES MORE WESTERLY AS PRESSURES ON THE PLAINS FALL AHEAD OF APPROACHING SOUTHWEST U.S. UPPER TROUGH. EXPECT FOG AND STRATUS TO CLEAR FAIRLY QUICKLY ALONG I-25...BUT HANG ON INTO EARLY AFTERNOON OVER THE LOWER ARKANSAS VALLEY FROM KPUB EASTWARD. THUS UNDERCUT GUIDANCE TEMPS ON THE PLAINS BY SEVERAL DEGREES. OVER THE MOUNTAINS...JUST ENOUGH MOISTURE AHEAD OF THE TROUGH TO ALLOW SNOW SHOWERS TO CONTINUE...THOUGH AGAIN AMOUNTS WILL BE LIGHT. .LONG TERM... (WEDNESDAY NIGHT THROUGH TUESDAY) LOOKING AT THE MODELS...THE ECMWF SEEMS TO BE WETTER THAN THE GFS WITH THE SYSTEMS MOVING ACROSS OUR AREA THROUGH THE WEEKEND...AND AMOUNTS ARE RATHER LIGHT...EVEN WITH THAT MODEL. THE STORM SYSTEM WILL CONTINUE SOUTHEAST ACROSS SOUTHERN NEW MEXICO THURSDAY NIGHT...WITH SOME MOISTURE DEVELOPING SHOWERS OVER MAINLY THE EASTERN SAN JUAN MOUNTAINS AND THE SOUTHERN SANGRE DE CRISTO MOUNTAINS. AMOUNTS WILL BE LIGHT...WITH SNOWFALL AMOUNTS IN THOSE AREAS GENERALLY AN INCH OR SO. FRIDAY WILL BE AN IN BETWEEN DAY AS UPPER FLOW SHIFTS TO THE NORTHWEST BEHIND THIS STORM. WITH WEAK WEATHER DISTURBANCES MOVING ACROSS COLORADO...SNOWFALL WILL OCCUR FROM TIME TO TIME OVER THE CENTRAL MOUNTAINS. AMOUNTS WILL GENERALLY BE LIGHT. ELSEWHERE IN OUR AREA...GENERALLY DRY CONDITIONS ARE EXPECTED. SATURDAY INTO SUNDAY A STORM SYSTEM WILL DIVE THROUGH COLORADO...BRINGING SNOW TO MAINLY THE CENTRAL MOUNTAINS AND UPPER ARKANSAS VALLEY. AN ARCTIC COLD FRONT IS EXPECTED TO MOVE THROUGH THE EASTERN PLAINS...WITH ENOUGH MOISTURE TO BRING SOME SNOW SHOWERS AND RAIN SHOWERS AT LOWER ELEVATIONS FOR A TIME AS THE STORM MOVES THROUGH THE AREA. UPSLOPE FLOW MAY CONTINUE THROUGH MOST OF SUNDAY AND INTO MONDAY BEHIND THIS WEAK FRONT. THIS SYSTEM WILL DEPART...LEAVING BEHIND ANOTHER PERIOD OF LIGHT SNOW OR SNOW SHOWERS IN NORTHWEST FLOW OVER THE MOUNTAINS INTO MONDAY. && .AVIATION... HAVE STRUGGLED WITH THE KCOS TAF ALL DAY...AS STRATUS AND FOG DISAPPEARED LATE MORNING ONLY TO REDEVELOP THIS AFTERNOON. DOUBT WE`LL SEE ANYTHING MORE THAN A BRIEF BREAK IN THE CLOUDS BEFORE CIGS THICKEN AND LOWER AFTER 02Z...WITH IFR TO BRIEFLY LIFR CONDITIONS THROUGH THE NIGHT. WITH WESTERLY FLOW DEVELOPING AFTER 09Z...SUSPECT STRATUS AND FOG WILL SLOWLY CLEAR BY 12Z WED...WITH VFR CONDITIONS THROUGH THE DAY. AT KPUB...EXPECT A RAPID REAPPEARANCE OF STRATUS AND FOG AFTER SUNSET...WITH SLOWER CLEARING THAN KCOS WED MORNING AS FOG LINGERS IN THE ARKANSAS VALLEY UNTIL 18Z. AT KALS...MUCH THE SAME FORECAST...WITH LOW CLOUDS AND FREEZING FOG DEVELOPING THIS EVENING...PERSISTING THROUGH MID-MORNING WED. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 10/51
