National Weather Service Forecast Discussion

000
FXUS65 KBOU 160923
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
323 AM MDT TUE MAR 16 2010

.SHORT TERM...NORTHERLY FLOW ALOFT WILL PERSIST TODAY AND TONIGHT AS
AN UPPER LEVEL RIDGE REMAINS CENTERED OVER THE GREAT BASIN AND AN
UPPER LEVEL TROUGH DIVES SOUTH ACROSS THE GREAT PLAINS. THE UPPER
LEVEL WILL DOMINATE THE WEATHER OVER COLORADO TODAY AND TONIGHT.
AIRMASS WILL BE DRY WITH ONLY A FEW HIGH CLOUDS AT TIMES. FOR THE
EASTERN PLAINS OF COLORADO...WINDS WILL BE NORTHERLY AT 10 TO 15 MPH
THIS AFTERNOON AS HIGH PRESSURE BUILDS IN BEHIND THE TROUGH OVER THE
GREAT PLAINS. ELSEWHERE...LIGHT DIURNAL WINDS WILL PREVAIL TODAY AND
TONIGHT. LOWER AIR MASS WARMS ABOUT 10F OVER YESTERDAY WHICH WILL
PUT HIGH TEMPERATURES IN THE UPPER 50S TO LOWER 60S FOR THE FRONT
RANGE AND EASTERN PLAINS. TEMPERATURES WILL BE ABLE TO COOL OFF INTO
THE MID 20S TO MID 30S TONIGHT DUE CLEAR SKIES...LIGHT WINDS AND DRY
AIRMASS.

.LONG TERM...FROM TRANQUIL SPRING-LIKE WEATHER TO WINTERY PRECIP AND
TEMPERATURES PRETTY MUCH SUMS UP THE LATTER HALF OF THE WEEK. STRONG
HIGH AMPLITUDE HIGH PRESSURE RIDGE MAKES ITS WAY ACROSS THE CENTRAL
ROCKY MTN REGION ON WEDNESDAY BRINGING WITH IT WARMER TEMPS AND
ESSENTIALLY CLEAR SKIES. MODELS SHOW 700MB TEMPS RISING INTO THE
3-4C RANGE BY WEDNESDAY AFTERNOON WHICH SHOULD EQUATE TO MAX TEMPS
IN THE LOWER/MID 60S ON THE PLAINS AND 40S/LOWER 50S IN THE HIGH
COUNTRY. LIGHT WLY FLOW OFF THE FRONT RANGE SHOULD HELP TO WARM THE
HIGH PLAINS AIRMASS WHILE THE FLOW ALOFT WILL BE LIGHT W-NWLY FOR
MOST OF THE DAY.

WEDNESDAY NIGHT INTO THURSDAY...THE UPPER RIDGE MOVES EAST WITH ITS
TOP FLATTENING ALONG THE WAY AS COLD AIR DROPS SOUTH OUT OF SWRN
CANADA WITH A VIGOROUS SHORTWAVE TROUGH. STILL LOOKING FOR ANOTHER
SPRING-LIKE DAY ON THURSDAY WITH NEAR ZONAL FLOW ALOFT AND W-SWLY
BNDRY LAYER WINDS ON THE PLAINS. THROUGH THE DAY SHOULD SEE WND SPDS
INCREASING AS A SW-TO-NE SFC PRES GRADIENT TIGHTENS IN RESPONSE TO
ADIABATIC WARMING AT THE BASE OF THE FOOTHILLS AND THE APPROACH OF A
STRONG COLD FRONT FROM THE NORTH-NORTHEAST. LOOKING FOR ANOTHER DAY
OF ABOVE AVERAGE SFC TEMPS WITH THE 700MB TEMP SIMILAR TO THE DAY
BEFORE. COULD SEE SFC TEMPS A SHADE WARMER IN BREEZY AREAS NEAR THE
FOOTHILLS AND IN THE SOUTH PLATTE RVR VALLEY ABOVE STERLING. HOWEVER
SHOULD MID AND HIGH LEVEL MOISTURE/CLOUD COVER ARRIVE SOONER THAN
EXPECTED THURSDAY HIGH PLAINS TEMPS MAY NOT REACH THE MID/UPPER 60S
AS I/M ANTICIPATING. BY LATE IN THE DAY SHOULD SEE CONVECTIVE
CONDENSATION LEVELS LOWERING OVER THE NRN MTNS WITH THE FORMATION OF
A FEW RAIN/SNOW SHOWERS. OTHERWISE EVERYWHERE ELSE WILL REMAIN
DRY.

THURSDAY NIGHT INTO FRIDAY...SUBTLE DIFFERENCES BEGIN TO SHOW UP IN
THE MODELS AT THIS TIME WHICH MAKE IT DIFFICULT TO PIN DOWN THE
ARRIVAL TIME OF THE STRONG COLD FRONT TO OUR NORTH. USING A BLEND OF
THE NAM...GFS...ECMWF...CANADIAN GLOBAL AND DGEX...IT APPEARS A SFC
LOW WILL FORM IN NERN COLORADO THURSDAY EVENING. CIRCULATION AROUND
THIS CYCLONE WILL AID IN DRIVING THE FRONTAL BNDRY DOWN THE FRONT
RANGE THEN OUT ACROSS THE NERN COLORADO PLAINS BY SOMETIME EARLY
FRIDAY MORNING. WE/LL PROBABLY SEE THE WARMEST TEMPS OF THE DAY
PRIOR TO ITS ARRIVAL. HAVE LOWERED FRIDAY TEMPS BY A FEW DEGS F
ACROSS THE ENTIRE CWFA TO ACCOUNT FOR STG COLD AIR ADVECTION AND
HEAVY CLOUD COVER. MAY NOT HAVE LOWERED TEMPS SUFFICIENTLY SHOULD
FROZEN PCPN BREAK OUT SOONER THAN EXPECTED. DURING THE DAY ON FRIDAY
MODELS SHOW THE POST FRONTAL E-NELY UPSLOPE FLOW STRENGTHENING AS
THE UPPER TROUGH CLOSES OFF OVER THE FOUR CORNERS AREA. MODELS SHOW
THE STRONGEST/DEEPEST QG ASCENT OVER FCST AREA FRIDAY
AFTERNOON/EVENING AS THE UPPER LOW TRACKS E-SEWRD ACROSS NRN NEW
MEXICO. MODELS SHOW THIS SYSTEM PRODUCING A DECENT AMOUNT OF QPF AND
SNOW ACCUMULATION ACROSS THE FCST AREA...ESPLY IN AREAS EAST OF
THE CONTINENTAL DIVIDE. FOR NOW WILL RAISE POPS...LOWER TEMPS AND
INCREASE SKY COVER FOR FRIDAY AND FRIDAY NIGHT AS THIS SYSTEM MAY
HANG AROUND LONGER THAN PREVIOUSLY THOUGHT.

SATURDAY AND BEYOND...CLEARING AND AN END TO PRECIPITATION MAY COME
SLOW ON SATURDAY AS THE MAJORITY OF THE MODELS SHOW THE AREA UNDER
THE INFLUENCE OF THE UPPER TROUGH AND WEAK UPSLOPE FLOW FOR MUCH OF
THE DAY. FOR THAT REASON HAVE LOWERED SATURDAY MAX TEMPS BY SEVERAL
DEGS. BY SUNDAY TROUGH IS OUT OF HERE BUT CONTINUED COLD AIR
ADVECTION WITH PREVAILING NLY FLOW WILL DELAY ANY NOTABLE WARMING
UNTIL NEXT WEEK. HOWEVER SUNDAY LOOKS DRY EXCEPT PERHAPS FOR A FEW
OROGRAPHIC SNOW SHOWERS LINGERING IN THE HIGH
COUNTRY.

&&

.AVIATION...VFR CONDITIONS AND LIGHT WILL PREVAIL THROUGH TONIGHT
DUE TO HIGH PRESSURE PARKED OVER THE REGION THROUGH TONIGHT. THIS
RIDGE WILL CONTINUE TO BRING CLEAR SKIES AND LIGHT DIURNAL WINDS
THROUGH WEDNESDAY MORNING.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...NONE.


$$
MEIER/BAKER

NWS BOU Office Area Forecast Discussion