FXUS65 KPUB 042200
AFDPUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
300 PM MST FRI DEC 4 2009
.SHORT TERM...
(TONIGHT AND SATURDAY)
...MAIN CHALLENGE IS TEMPERATURES...
CURRENTLY...GENERALLY MOSTLY SUNNY OVER THE CWA WITH SOME MIDDLE
AND HIGH CLOUDS MOVING IN FROM THE NORTHWEST. TEMPERATURES ON THE
PLAINS AND IN THE MOUNTAIN VALLEY ARE COLD...BUT SOME WARMING IS
EVIDENT AT THE HIGHER ELEVATIONS. THE WILLIS CREEK RAWS AT 9000
FEET IS 33 AND THE BOSQUE RAWS IS 32. SOME HIGHER ELEVATION SITES
ARE SHOWING SOME GUSTY WEST TO SOUTHWEST WINDS AS THE DISTURBANCE
APPROACHES.
.TONIGHT...AS THE DISTURBANCE APPROACHES WINDS ALOFT WILL INCREASE.
RAOBS THIS MORNING SHOWING SOME RELATIVELY MILD AIR ALOFT TO THE
WEST OF COLORADO...WHICH WILL MOVE INTO THE REGION TONIGHT. IN THE
TEMPERATURE FIELDS...TRIED TO DEPICT A THERMAL BELT OVER THE LEE OF
THE EASTERN MOUNTAINS. COLD AIR WILL REMAIN TRAPPED ALONG THE
ARKANSAS RIVER AND IN THE MOUNTAIN VALLEYS FOR COLD OVERNIGHT
LOWS. INCREASED MINIMUMS A FEW DEGREES ALONG THE NEW MEXICO BORDER
AS SOUTHWEST WINDS WITH LEE TROUGH WILL KEEP SOME MIXING. ALONG THE
SOUTHERN INTERSTATE 25 CORRIDOR...LOWS MAY BE HIGHER THAN IN CURRENT
GRIDS IF WARMER SOUTHWEST FLOW ALOFT CAN MIX TO THE SURFACE.
.SATURDAY...AIR ALOFT REMAINS RELATIVELY MILD THROUGH MUCH OF THE
DAY. MAIN CHALLENGE IS THE TIMING OF THE SURFACE FRONT. HAVE THE
FRONT PASSING THROUGH THE PLAINS DURING THE MIDDAY. THE COLD AIR
WILL GRADUALLY FILTER SOUTHWARD DURING THE LATE AFTERNOON...SO DO
NOT EXPECT A STRONG TEMPERATURE DROP INITIALLY BEHIND THE FRONT.
OVER THE MOUNTAINS...SOME MOISTURE STARTS REACHING THE CENTRAL
MOUNTAINS DURING THE AFTERNOON...AND MAINTAINED THE ISOLATED POPS.
.LONG TERM...
(SUNDAY-FRIDAY)
...TWO STRONG SHORT WAVES ENFORCED WITH ARCTIC AIR TO AFFECT THE
REGION DURING THIS PERIOD...
MODELS CONTINUE TO INDICATE TWO STRONG SHORT WAVES WILL AFFECT THE
REGION. BOTH OF THESE SYSTEMS WILL HAVE REINFORCING SHOTS OF COLD
AIR WITH THEM. LIKEWISE...WX WILL BE QUITE ACTIVE DURING A GOOD PART
OF THIS PERIOD.
BY SAT EVE (00Z SUNDAY) THE FIRST SYSTEM WILL BEGIN AFFECTING THE
REGION. COLDER AIR WILL BE WORKING ITS WAY SOUTH DOWN THE PLAINS BY
SAT EVENING...AND SKIES WILL QUICKLY BECOME OVERCAST OVER THE
REGION BY MID EVENING. SNOWS WILL BEGIN TO INCREASE OVER THE CENTRAL
MOUNTAINS AND WILL PICK UP AFTER MIDNIGHT. ON THE PLAINS...DO NOT
EXPECT ANY SNOW TO START FALLING UNTIL AFTER MIDNIGHT...AND MOST OF
THIS ACTIVITY WILL BE OVER THE GREATER PIKES PEAK REGION.
MOST OF THE ENERGY WITH THE FIRST SYSTEM WILL REMAIN GENERALLY N OF
HIGHWAY 50...SO MOST OF THE PRECIP THAT FALLS WILL BE NORTH OF THIS
HIGHWAY. HOWEVER...THE COLD AIR WITH THE SYSTEM WILL AFFECT THE
ENTIRE REGION AND EXPECT HIGH TEMPS ON SUNDAY TO ONLY BE IN THE 20S.
IT WILL BE CLOUDY ALL AREAS ON SUNDAY. AS FOR SNOW...WE SHOULD SEE 4
TO 8 INCHES OF SNOW OVER THE C MTNS...AND THE PIKES PEAK REGION
SHOULD SEE 2-6"...WITH LOWER AMOUNTS ACROSS N EL PASO...AND HIGHER
AMOUNTS ACROSS PIKES PEAK. IT WILL BE A BIT WINDY OVER THE MTN TOPS.
A BIT OF REPRIEVE WILL OCCUR ACROSS THE REGION SUNDAY NIGHT INTO
MONDAY...ALTHOUGH ALL AREAS SHOULD REMAIN CLOUDY AND COLD AND I
CANNOT RULE OUT SOME LIGHT S- ACROSS THE REGION.
A MUCH MORE POTENT SYSTEM WILL BEGIN AFFECTING THE REGION BY LATER
MONDAY. I AM QUITE CONCERNED ABOUT THIS SYSTEM AS THERE IS GOING TO
BE ALOT OF ENERGY WITH THIS SYSTEM ALONG WITH LOTS OF BAROCLINICITY.
LATEST SIMULATIONS SHOW THIS SYSTEM MOVING ACROSS AS AN INTENSE OPEN
WAVE ALTHOUGH EARLIER RUNS WERE SHOWING THE SYSTEM MORE CUT OFF. FOR
NOW IT APPEARS THAT THE SW MTNS WILL SEE A MAJOR EVENT WITH THIS
STORM AS 50-70 KNT SW 700 MB FLOW WILL IMPINGE ONTO THIS MTN BARRIER
STARTING EARLY MONDAY MORNING AND LASTING INTO TUESDAY. SEVERAL FEET
OF SNOW IS LIKELY GIVEN THE STRONG OROGRAPHICS AND THERMODYNAMICS.
BY 12Z TUESDAY...INTENSE - 200+ MPH - JET WILL BE ROUNDING THE BASE
OF THE BROAD TROUGH WHICH WILL BE LOCATED VICINITY OF THE 4 CORNERS.
BY THIS TIME AN ALREADY IMPRESSIVE 988 MB LOW WILL BE OVER THE
SW MTNS OF COLORADO. HOWEVER...BOTH GFS AND EC MOVE THIS STRONG
SYSTEM RATHER QUICKLY EAST AND IT IS FCST TO BE LOCATED OVER C KS
BY 00Z WED. I AM MORE THAN A BIT CONCERNED THAT THE MODELS ARE NOT
HANDLING THIS SYSTEM ALL THAT WELL AND WOULD NOT BE AT ALL
SURPRISED IF THE THING WRAPS UP MORE ON THE EASTERN PLAINS ON
TUESDAY. EITHER WAY WE WILL LIKELY SEE SOME SNOW...POSSIBLY HEAVY
FOR A FEW HOURS (OR MORE) ON THE PLAINS TUESDAY AS THE SYSTEM GOES
BY. ONCE IT GOES BY...ARCTIC AIR TO THE N OF THE SYSTEM WILL BLAST
SOUTH.
IF THIS SYSTEM SHOULD SLOW UP WE COULD BE DEALING WITH A POTENTIALLY
HIGH IMPACT EVENT OVER THE PLAINS. AS MENTIONED ABOVE...THEIR WILL
BE LOTS OF BAROCLINICITY FOR THIS SYSTEM TO PLAY WITH AND LOTS OF
FORCING GIVEN THE JET (HOW OFTEN TO YOU SEE A PRGD 987 MB LOW OVER
UTAH ON THE 12Z 04 DEC GFS VERIFYING AT 06 UTC TUESDAY???). AS FOR
THE MODEL SOLUTIONS...I AM HAVING A DIFFICULT TIME UNDERSTANDING THE
PLACEMENT OF THE LOWER ATMOSPHERIC CYCLONE CENTERS OVER CO ON
TUESDAY AS THEY APPEAR TOO FAR NORTH GIVEN THE JET PLACEMENT AND THE
OROGRAPHICS. ALSO THE SPEED OF THE SYSTEM JUST LOOKS TOO FAST GIVEN
THE FORCING.
THERE IS STILL LOTS OF TIME TO SEE HOW THINGS EVOLVE. BUT...I WOULD
NOT BE TOO SURPRISED IF WE ARE DEALING WITH A HIGH IMPACT EVENT ON
THE PLAINS ON TUESDAY.
AS FOR THE REST OF THE FCST...LOTS OF STRONG ZONAL FLOW WITH
EMBEDDED SHORT WAVES THROUGH LATER NEXT WEEK SO EXPECT THE MTN SNOWS
ALONG THE CONTDVD TO CONTINUE. I DID BRING DOWN TEMPS A FEW DEGREES
THROUGH THE PERIOD. \/HODANISH
&&
.AVIATION...
VFR AT THE TAF SITES WITH LIGHT WINDS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
06/34
