069
FXUS65 KPUB 091058
AFDPUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
358 AM MST TUE FEB 9 2010
SHORT TERM
(TODAY AND TONIGHT)
CURRENTLY...RADAR STILL INDICATING AREAS OF LIGHT SNOWFALL ALONG THE
EASTERN MOUNTAINS AND I-25 CORRIDOR EARLY THIS MORNING. RADAR ECHO
TRENDS HAVE BEEN ON THE DECREASE OVER THE PAST COUPLE OF HOURS AND
EXPECT SNOW TO DISSIPATE OVER THE PLAINS OVER THE NEXT FEW HOURS.
SATELLITE IMAGERY INDICATING STRATUS DECK OVER THE EASTERN PLAINS
WHICH HAS KEPT TEMPERATURES IN THE TEENS. NOT ANTICIPATING FOG
DEVELOPMENT THIS MORNING WITH DEW POINT DEPRESSIONS RUNNING GREATER
THAN 4 DEGREES OVER THE PLAINS AND SAN LUIS VALLEY.
MAIN FORECAST CHALLENGES FOR TODAY...TEMPERATURES AND LIGHT SNOW.
UPPER LEVEL LOW PRESSURE SYSTEM WILL TRACK EASTWARD INTO THE OHIO
VALLEY BY THIS AFTERNOON WITH HIGH PRESSURE BUILDING OVER THE FOUR
CORNERS REGION. MODELS ALL IN GENERAL AGREEMENT WITH A WEAK
DISTURBANCE TRACKING UNDER THE RIDGE AND ACROSS SOUTHERN COLORADO
LATE THIS AFTERNOON. BIGGEST CHALLENGE THIS AFTERNOON WILL BE THE
CHANCE FOR SNOW OVER THE EASTERN MOUNTAINS AND ADJACENT PLAINS.
MODEL GUIDANCE SHIFTS WIND FROM THE SURFACE THROUGH 850 MB EAST TO
SOUTHEASTERLY BY 21Z...HOWEVER FLOW WILL REMAIN WEAK AT OR BELOW 10
KTS. THERE WILL ALSO BE WEAK WARM AIR ADVECTION IN THE MID LEVELS
ASSOCIATED WITH THE WEAK VORT MAX PASSING ACROSS THE REGION.
UPSLOPE FLOW IN THE LOWER LEVELS COMBINED WITH WEAK LIFT IN THE MID
LEVELS MAY BE ENOUGH TO GENERATE LIGHT SNOW THIS AFTERNOON AND
EVENING FOR THE EASTERN MOUNTAINS AND ADJACENT PLAINS. MODELS NOT
IN AGREEMENT ON OCCURRENCE...NAM AND WRF ARE DRY...GFS IS MOST
AGGRESSIVE WITH QPF. FOR NOW POSTED SLIGHT CHANCE FOR SNOW OVER THE
EASTERN MOUNTAINS AND ADJACENT PLAINS FROM 21Z THROUGH 03Z BEFORE LOW
LEVEL FLOW SHIFTS SOUTHWESTERLY AND THE MID LEVEL LIFT DISSIPATES.
ANY ADDITIONAL ACCUMULATIONS WILL REMAIN LIGHT WITH LESS THAN AN
INCH OF NEW SNOWFALL. TEMPERATURES WILL BE THE OTHER FORECAST
CHALLENGE. STRATUS DECK FORECAST TO REMAIN ENTRENCHED OVER THE
EASTERN PLAINS KEEPING TEMPERATURES FROM WARMING. CURRENTLY ON THE
LOW END OF GUIDANCE WITH HIGHS IN THE LOWER TO MID 20S WHICH MAY BE
A BIT TOO WARM.
HIGH PRESSURE MOVES OVERHEAD TONIGHT WITH SNOW COMING TO AN END OVER
THE EASTERN MOUNTAINS AND ADJACENT PLAINS BY 06Z. MODEL SOUNDINGS
INDICATING FOG DEVELOPMENT ALONG THE ARKANSAS RIVER VALLEY AND SAN
LUIS VALLEY BY WEDNESDAY MORNING. STRATUS DECK WILL KEEP
TEMPERATURES MODERATED ONCE AGAIN WITH LOWS IN THE TEENS. MOZLEY
LONG TERM
(WEDNESDAY THROUGH MONDAY)
AN UPR LOW WL BE MOVING INTO NRN BAJA CA ON WED WITH WESTERLY FLOW
ALOFT OVR THE CWA. SOME MSTR IN THAT WRLY FLOW WL PROBABLY BRING
SOME LIGHT SNOW TO AREAS ALONG THE CONTDVD...WITH THE REST OF THE
AREA BEING DRY. ONE CONCERN FOR THE DAY WILL BE THE EXTENT OF LOW
CLOUDS OVR PORTIONS OF THE SERN PLAINS. IT LOOKS LIKE WE WL SEE
SOME FOG AND LOW CLOUDS OVR THE SAN LUIS VALLEY WED
MORNING...WHICH SHOULD THEN DISSIPATE BY LATE MORNING. LOW LEVEL
MSTR FIELDS IN THE NAM ARE ALSO SHOWING THE POTENTIAL FOR
WIDESPREAD LOW CLOUDS AND SOME FOG WED MORNING ACROSS THE FAR SERN
PLAINS...AND ALSO EXTENDING WESTWARD TO PUEBLO AND INTO SRN
PORTIONS OF EL PASO COUNTY. THE NAM KEEPS LOW LEVEL UPSLOPE FLOW
OVR MUCH OF THE SE PLAINS THRU THE DAY WED AND TRIES TO HOLD ONTO
MUCH OF THE LOW CLOUDINESS THEN THRU THE AFTERNOON...ALTHOUGH FOG
WL LIKELY DECREASE. IF THESE LOW CLOUDS REMAIN IN PLACE TEMPS WL
REMAIN QUITE COOL. THERE ARE SOME SIGNIFICANT DIFFERENCES BETWEEN
THE MET AND MAV GUIDANCE TEMPS FOR WED OVR THE SE PLAINS WITH THE
MET BEING MUCH COLDER THAN THE MAV. WL KEEP THINGS ON THE COOL
SIDE. A WEAK SHRTWV TROF DROPS ACRS THE ERN PLAINS WED NIGHT BUT
THE MODELS KEEP THE FORECAST DRY FOR THE EAST. MOIST WEST TO NW
FLOW ALONG THE CONTDVD WL LIKELY STILL PRODUCE SOME LIGHT SNOW.
THU AN UPR RIDGE WL BE BUILDING OVR THE GREAT BASIN WHICH WL IN
TURN BRING INCREASED NW FLOW OVR THE FORECAST AREA FOR THU AND THU
NIGHT. AT THE SAME TIME THAT UPR LOW WL BE MOVING EWRD ACRS NRN
MEXICO AND INTO WRN TX. THE AREA SHOULD GENERALLY BE DRY...BUT WE
COULD STILL SEE SOME LIGHT PCPN OVR THE CONTDVD. TEMPS THU SHOULD
BE A LITTLE WARMER. MUCH THE SAME FOR FRI AS NW FLOW ALOFT
CONTINUES OVR THE AREA...BUT FRI NIGHT AND SAT A NEW SHRTWV TROF
MOVES ACRS CO BRINGING A BETTER CHANCE FOR SNOW TO THE CENTRAL
MTS...AND POSSIBLY SOME LIGHT PCPN TO SE CO. FOR SUN THE GFS SHOWS AN
UPR RIDGE BUILDING OVR THE AREA WITH LITTLE CHANCE FOR
PCPN...WHILE THE ECMWF HAS THE RIDGE TO OUR WEST AND SHOWS A
SHRTWV TROF MOVING ACRS THE AREA...AND POSSIBLY BRINGING SOME PCPN
CHANCES. GENERALLY DRY...NW FLOW IS EXPECTED MON.
AVIATION
FLURRIES AND LIGHT SNOW WILL CONTINUE THROUGH MUCH OF THE DAY AT
KCOS AND KPUB WITH THE BEST CHANCE OF LIGHT SNOW THIS AFTERNOON FROM
21Z THROUGH 03Z. EXPECT MVFR CONDITIONS THROUGH MUCH OF THE DAY
WITH OCCASIONAL IFR CONDITIONS POSSIBLE THIS AFTERNOON. STRATUS
DECK WILL REMAIN IN PLACE ACROSS THE PLAINS THROUGH TONIGHT WITH
CIGS GENERALLY 3KFT TO 5KFT. SNOW WILL COME TO AN END FOR KCOS AND
KPUB AFTER 03Z WITH FOG DEVELOPING BY 06Z PRODUCING IFR TO LIFR
CONDITIONS THROUGH WEDNESDAY MORNING. EXPECT STRATUS OVER KALS
THROUGH THE DAY WITH MVFR TO IFR CONDITIONS. FOG IS FORECAST TO
DEVELOP OVER THE SAN LUIS VALLEY OVERNIGHT IMPACTING KALS THROUGH
WEDNESDAY MORNING WITH IFR TO LIFR CONDITIONS OVERNIGHT. MOZLEY
PUB WATCHES/WARNINGS/ADVISORIES
NONE.
88/28
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