315
FXUS65 KBOU 160853
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
253 AM MDT WED OCT 16 2013
.SHORT TERM...SHARPLY TILTED UPPER TROUGH AND LOW CENTER CONTINUE
THEIR SLOW EASTWARD PROGRESS ACROSS COLORADO AT THIS TIME. ON
SATELLITE IMAGERY...THE MID-LEVEL CIRCULATION APPEARED TO BE
CENTERED IMMEDIATELY NORTHEAST OF THE FOUR CORNERS. INCREASING CLOUD
ENHANCEMENT SHOWING UP ON IR SAT IMAGERY OVER SOUTH CENTRAL AND
SOUTHEAST COLORADO ASSOCIATED WITH WARM ADVECTION/ISENTROPIC LIFT
OUT AHEAD OF THE UPPER LOW. AREA OF ENHANCEMENT EXTENDS AS FAR NORTH
AS THE PALMER DIVIDE. IN THE PAST HOUR NWS DEN AND PUB RADARS
DETECTED A MODEST INCREASE IN PRECIP ECHO COVERAGE ACROSS SOUTHEAST
COLORADO. NOW SEE A FEW ECHOS POPPING OVER THE FOOTHILLS IN
DOUGLAS COUNTY AND THE SOUTHWEST TIP OF LINCOLN COUNTY. THE STRONGER
RADAR RETURNS REMAIN WELL SOUTH OF THE AREA. OVER THE NEXT SEVERAL
HOURS NAM...GFS...WRF AND EUROPEAN MODELS ALL SHOW THE UPPER LOW
WITH ITS LIFT AND PRECIPITATION FIELDS TRACKING EASTWARD ALONG
THE SOUTHEAST COLORADO/NORTHEAST NEW MEXICO BORDER. SOUTHERN
PORTIONS OF OUR FORECAST AREA MAY CATCH SOME OF THE NORTHERN EDGE
OF THIS SYSTEM IN THE FORM OF A FEW SNOW SHOWERS GENERALLY OF
LIGHT INTENSITY. SOUTH PARK AND FOOTHILL AREAS WEST/SOUTHWEST OF
DENVER MAY ALSO SEE AN UPTICK IN PRECIP FORMATION IN THE NEXT FEW
HOURS. HOWEVER ANY QPF/SNOW ACCUMULATION SHOULD BE MINIMAL IF ANY.
HOWEVER ALL BUT THE FAR NORTHEAST CORNER OF THE CWFA WILL LIKELY
REMAIN UNDER MOSTLY TO OVERCAST SKIES THROUGH THE EARLY MORNING
HOURS...AT LEAST UNTIL THE UPPER LOW MOVES EAST OF THE AREA AND
THE 850-600 MB TURNS NORTHWESTERLY. OVERALL..THE FREEZE WARNING
OVERNIGHT VERIFIED. AT THE PRESENT TIME...TEMPERATURES ON THE
PLAINS IN THE MID TO UPPER 20S ALL EXCEPT IN BOULDER COUNTY WHERE
THE LOW CLOUD COVER HAS HELD TEMPERATURES TO THE LOW/MID 30S. WITH
ANY CLEARING DURING THE NEXT FEW HOURS...WARNING SHOULD VERIFY
THERE...TOO.
FOR THE REMAINDER OF TODAY...THE UPPER TROUGH MOVES OUT ALLOWING
DRIER AIR TO FILTER DOWN FROM WYOMING RESULTING IN GRADUAL CLEARING
FROM NORTH TO SOUTH. RETURN OF SUNSHINE BY AFTERNOON SHOULD RETURN
TEMPERATURES TO THE 50S ON THE PLAINS. CLEARING WON/T BE AS QUICK IN
THE HIGH COUNTRY SO ONLY SLIGHTLY WARMER UP THERE TODAY. HIGHER
ELEVATIONS SHOULD ALSO SEE THE LAST OF THE FEW REMAINING LIGHT SNOW
SHOWERS BY LATE MORNING OR EARLY AFTERNOON. FOR THE MOST PART WINDS
WILL BE LIGHT TODAY EXCEPT IN THE FAR NORTHEAST WHERE NWLY WINDS OF
10-20KTS EXPECTED TO DEVELOP THIS AFTERNOON WITH INCREASING
NORTHWESTERLY FLOW ALOFT ON THE BACK SIDE OF THE TROUGH.
OVERNIGHT...A WEAK SHORTWAVE RIDGE EMBEDDED IN NORTHWESTERLY FLOW
ALOFT WILL PASS OVERHEAD. CLEAR SKIES...CHILLY TEMPERATURES AND
LIGHT WINDS WILL BE THE RULE. ALTHOUGH THE FAR NORTHEAST CORNER MAY
CONTINUE TO SEE NORTHWEST WINDS OF 10-15 KTS FOR MUCH OF THE NIGHT
IN RESPONSE TO STRENGTHENING NORTHWESTERLY FLOW ALOFT.
.LONG TERM...FOR MUCH OF THE LONG TERM FORECAST COLORADO WILL BE
UNDER A MODERATE NORTHWEST FLOW PATTERN AS HIGH PRESSURE RIDGING
ALOFT REMAINS OFF THE WEST COAST. WITHIN THE FLOW...AN UPPER
LEVEL DISTURBANCE WILL MOVE ACROSS COLORADO THURSDAY NIGHT AND
FRIDAY MORNING WITH THE NEXT SHOT OF PRECIP FOR THE AREA. OVER THE
PAST FEW RUNS THE MODELS HAVE BECOME VERY CONSISTENT WITH THIS
WAVE AND TIMING. HENCE...WITH INCREASING CONFIDENCE WILL CONTINUE
THE UPWARD TREND IN CHANCES OF RAIN AND SNOW. AN ASSOCIATED COLD
FRONT WILL MOVE INTO NORTHEAST COLORADO THURSDAY AFTERNOON WITH
SHALLOW UPSLOPE FLOW DEVELOPING. INITIALLY THE AIRMASS WILL BE DRY
BUT EXPECT INCREASING MOISTURE DURING LATE THURSDAY AFTERNOON AND
EVENING. APPEARS THERE WILL BE ENOUGH COOLING FOR MOST LOCALES TO
SEE SNOW LATE THURSDAY NIGHT AND INTO FRIDAY MORNING AS AIRMASS
SATURATES. OVERALL QPF FROM MODELS IS RANGING FROM .10 TO UP TO
.50" OF AN INCH SO CONCEIVABLE THAT THE NORTHEAST PLAINS AND
MOUNTAINS MAY SEE A COUPLE OF INCHES OF SNOW FROM THIS SYSTEM.
THERE IS SOME MODEST QG FORCING ALOFT AS THIS SYSTEM PASSES ACROSS
COLORADO. THE SNOW WILL END FROM NORTH TO SOUTH ON FRIDAY MORNING
WITH A RETURN TO DRY CONDITIONS FROM LATE FRIDAY THROUGH THE
WEEKEND.
THERE IS ANOTHER WEAK WAVE THAT BRUSHES NORTHEAST COLORADO SUNDAY
NIGHT AND MONDAY BUT FOR NOW MOISTURE LOOKS QUITE LIMITED WITH
THIS SYSTEM. WITH THE NORTHWEST FLOW PATTERN A STRONGER JET
STREAK WILL APPROACH NORTHEAST COLORADO LATE MONDAY AND TUESDAY
WITH SOME MOISTURE. BEING THAT FAR OUT WILL KEEP THINGS DRY FOR
NOW.
&&
.AVIATION...LOW CLOUD CEILINGS IN THE 3000-5000 FT AGL RANGE IN
THE DENVER AREA AS OF 09Z/WED. LOWER CEILINGS FOUND IN THE MTNS
AND FOOTHILLS. LOW CLOUDS OVER AND NEAR THE FOOTHILLS WEST AND
SOUTHWEST OF DENVER PRODUCING SNOW FLURRIES AT THIS TIME. DO NOT
EXPECT TO SEE MORE THAN A FEW FLURRIES AT DENVER AREA AIRPORTS
NOW THROUGH 15Z THIS MORNING. OTHERWISE CEILINGS IN THE DENVER
AREA SHOULD BEGIN LIFTING NOT LONG AFTER SUNRISE (13Z-14Z)...WITH
VFR CEILINGS BY MID-MORNING...AND PARTLY CLOUDY SKIES BY MIDDAY.
THE OUTLOOK IS FOR VARIABLE WINDS GENERALLY UNDER 10 KTS TODAY.
TONIGHT EXPECT TYPICAL DRAINAGE WINDS UNDER 8 KTS UNDERNEATH A
CLEAR TO MOSTLY CLEAR SKY.
&&
.HYDROLOGY...NO CONCERNS AT THIS TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 9 AM MDT THIS MORNING FOR COZ038-039-
042>044-048>051.
&&
$$
SHORT TERM...BAKER
LONG TERM....ENTREKIN
AVIATION...BAKER