Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 221043
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
443 AM MDT SUN MAR 22 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 443 AM MDT SUN MAR 22 2015

UPPER LEVEL RIDGING WILL CONTINUE OVER COLORADO TODAY WITH
TEMPERATURES WELL ABOVE SEASONAL NORMALS. THERE WILL BE A MODEST
INCREASE IN MOISTURE ALOFT THROUGH THIS AFTERNOON AND EVENING AS
THE UPPER RIDGE BEGINS WEAKENING AHEAD OF AN UPPER TROUGH MOVING
OUT OF THE PACIFIC NORTHWEST. THE NAM AND GFS GENERATE SHOWER
ACTIVITY OVER THE MOUNTAINS THIS AFTERNOON AND EVENING...BUT THE
LATEST RUNS OF THE RAP KEEP CONDITIONS OVER COLORADO DRY THROUGH
03Z. WATER VAPOR IMAGERY SHOWS INCREASED MOISTURE OVER NEVADA AND
UTAH BUT INFRARED SATELLITE PICTURES ONLY SHOW INCREASING CLOUDS
OVER EASTERN UTAH AT THIS TIME. SINCE THE PREVIOUS FORECAST
ALREADY HAD SOME LOW POPS IN THE MOUNTAINS THIS AFTERNOON AND
EVENING...WILL STICK WITH THAT FOR NOW. WITH THE AIRMASS STARTING
OUT SO WARM...WILL MENTION THE PRECIPITATION BEGINNING AS RAIN OR
A MIX OF RAIN AND SNOW. POPS WILL MAX OUT IN THE 40-50 PERCENT
RANGE DURING THE LATTER HALF OF THE AFTERNOON.

WINDS ACROSS NORTHEAST COLORADO TODAY MAY BE AFFECTED BY A WEAK
SURFACE FRONT MOVING OUT OF WYOMING. CURRENTLY...ANY PRESSURE
RISES OVER WYOMING ARE WEAK...BUT AS THE LEE TROUGH THAT HAS BEEN
IN PLACE OVER NORTHEAST COLORADO MOVES AWAY FROM THE FOOTHILLS
WINDS SHOULD BECOME NORTHERLY LATE IN THE MORNING AND
NORTHEASTERLY LATER IN THE AFTERNOON. THE COMBINATION OF WEAK
NORTH WINDS AND GRADUALLY INCREASING CLOUDS SHOULD KEEP HIGH
TEMPERATURES AT AROUND THE SAME NUMBERS THEY WERE YESTERDAY
AFTERNOON.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 443 AM MDT SUN MAR 22 2015

THE FLOW ALOFT WILL BECOME MORE WSW ON MON AHEAD OF AN UPPER LVL
THAT WILL MOVE QUICKLY ACROSS WY AND NRN CO MON NIGHT.  AT THE SFC
LOW PRES WILL INTENSIFY FM ERN WY INTO ERN CO WITH INCREASING SSE
LOW LVL FLOW ACROSS THE PLAINS.  CROSS-SECTIONS SHOW MOISTURE WILL
INCREASE IN THE MTNS BY LATE AFTN SO WILL KEEP IN A CHC OF SHOWERS
MAINLY NORTH OF I-70.  ACROSS THE PLAINS IT WILL BE MAINLY DRY
EXCEPT FOR A SLIGHT CHC OF CONVECTION NR THE WY-CO BORDER.  AS FOR
HIGHS WILL KEEP READINGS IN THE UPPER 60S TO LOWER 70S ACROSS NERN
CO.

FOR MON NIGHT INTO EARLY TUE A QUICK MOVING UPPER LEVEL TROUGH WILL
AFFECT THE AREA WITH A DECENT SHOT OF MID LVL ASCENT ALONG WITH
RATHER STEEP LAPSE RATES.  THUS SHOULD SEE SNOW INCREASE IN THE MTNS
MON EVENING BUT THEN DECREASE BY TUE MORNING.  SOME AREAS COULD GET
CLOSE TO LOWER END ADVISORY AMOUNTS NORTH OF I-70. AT LOWER
ELEVATIONS WITH STEEP LAPSE RATES AND FAVORABLE MID LVL ASCENT
THERE WILL BE A CHC OF SHOWERS AND A FEW TSTMS MON NIGHT
ESPECIALLY NR THE WY-NE BORDER WITH LOWER CHANCES FURTHER SOUTH.

ON TUE THE UPPER LEVEL TROUGH WILL EXIT THE AREA TUE MORNING WITH
STG DOWNWARD DESCENT THRU THE AFTN HOURS.  ALTHOUGH OROGRAPHICS WILL
REMAIN FAVORABLE IN THE MTNS MOISTURE DEPTH WILL BE MARGINAL THRU
THE AFTN SO ANY ADDITIONAL ACCUMULATIONS WILL BE ON THE LIGHT SIDE.
OVER NERN CO WITH STG DOWNWARD FORCING IN PLACE DO NOT EXPECT ANY
PCPN ALTHOUGH THERE COULD BE A FEW LINGERING SHOWERS OVER THE FAR
NERN CORNER IN THE MORNING.  MEANWHILE WITH DECENT LOW LVL GRADIENT
IN PLACE AND DOWNWARD DESCENT EXPECT FAIRLY STG WINDS FM THE NRN
FOOTHILLS ACROSS THE PLAINS.  WINDS COULD GET CLOSE TO WARNING
CRITERIA FOR A FEW HOURS ESPECIALLY CLOSER TO THE WY-NE BORDER.
ALSO CONSIDERING HOW DRY IT HAS BEEN OVER PORTIONS OF THE PLAINS
BLOWING DUST WILL CERTAINLY BE POSSIBLE AS WELL.  AS FOR HIGHS
READINGS WILL COOL BACK INTO THE LOWER TO MID 60S OVER NERN CO.

FOR TUE NIGHT AND WED THE FLOW ALOFT WILL BECOME MORE NWLY WITH A
DISTURBANCE POSSIBLY AFFECTING THE AREA ON WED. MOISTURE WILL
INCREASE IN THE MTNS WITH FAVORABLE OROGRAPHICS AND LAPSE RATES SO
SHOULD SEE A GOOD CHC OF SNOW.  AT LOWER ELEVATIONS A CDFNT WILL
MOVE ACROSS NERN CO LATE TUE NIGHT INTO WED MORNING WITH NLY LOW LVL
FLOW.  AS THE DISTURBANCE MOVES ACROSS DURING THE DAY THERE MAY BE
AT LEAST A SLIGHT CHC OF LIGHT PCPN BEHIND THE FNT SO WILL KEEP IN
LOW POPS OVER NERN CO.  AS FOR HIGHS THE ECWMF HAS READINGS IN THE
40S OVER NERN CO WHILE THE GFS HAS TEMPS IN THE 50S.  FOR NOW WILL
KEEP HIGHS IN THE LOWER TO MID 50S.

FOR WED NIGHT INTO THU NWLY FLOW ALOFT WILL REMAIN OVER THE AREA.
THE ECMWF AND GFS STILL DISAGREE AS TO HOW MUCH MOISTURE IS EMBEDDED
IN THE FLOW AND WHETHER ANOTHER SURGE OF COOLER AIR WILL AFFECT NERN
CO.  THE ECMWF CONTINUES TO SHOW VERY LITTLE MOISTURE ON THU AND
DOES NOT HAVE ANOTHER FNT AFFECTING THE PLAINS.  AS A RESULT IT HAS
NO PCPN AND SHOWS WARMER TEMPS. MEANWHILE THE GFS HAS SOME
MOISTURE EMBEDDED IN THE FLOW AND SHOWS ANOTHER FNT MOVING ACROSS
NERN CO DURING THE DAY. THIS LEADS TO A CHC OF SNOW IN THE MTNS
AND POSSIBLY SOME LIGHT PCPN OVER NERN CO. WILL CONTINUE TO KEEP
POPS ON THE LOW SIDE ON THU SINCE THERE IS NO AGREEMENT BETWEEN
THE TWO MODELS. AS FAR AS HIGHS WILL KEEP READINGS IN THE 50S OVER
NERN CO.

BY FRI AND SAT BOTH THE ECMWF AND GFS SHOW DRY NWLY FLOW ALOFT OVER
THE AREA WITH NO PCPN.  HIGHS WILL GRADUALLY RISE BOTH DAYS WITH 70S
POSSIBLY BY SATURDAY OVER NERN CO.


&&

.AVIATION...(FOR THE TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 443 AM MDT SUN MAR 22 2015

NO AVIATION IMPACTS FROM WEATHER TODAY AND TONIGHT. HIGH CLOUDS
WILL BE GRADUALLY INCREASING THIS AFTERNOON AND OVERNIGHT BUT
CEILINGS SHOULD REMAIN ABOVE 8000 FEET AGL. SOUTHERLY WINDS THIS
MORNING ARE EXPECTED TO SWITCH TO NORTHERLY LATE IN THE MORNING
THEN NORTHEAST TO EASTERLY LATE IN THE AFTERNOON AND EVENING.

&&

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

$$

SHORT TERM...DANKERS
LONG TERM...RPK
AVIATION...DANKERS



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