Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 250959
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
359 AM MDT WED MAR 25 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 350 AM MDT WED MAR 25 2015

A DISTURBANCE IN NW FLOW ALOFT WILL MOVE ACROSS THE AREA TODAY.
THIS FEATURE HAS FAVORABLE MID LVL ASCENT AND LAPSE RATES WITH IT
THRU LATE AFTN.  AT LOWER ELEVATIONS A CDFNT WILL MOVE ACROSS NERN
CO WITH THE LOW LVL FLOW MAINLY NLY BEHIND THE FNT.

IN THE MTNS WILL SEE PERIODS OF SNOW THRU MIDDAY HOWEVER BY AFTN
SOME DRIER AIR WILL SPREAD ACROSS AS MID LVL DESCENT DVLPS.  THUS
SNOW SHOULD BEGIN TO DECREASE THRU THE AFTN HOURS.

OVER NERN CO FCST IS MORE COMPLICATED.  WITH NLY LOW LVL FLOW AREAS
CLOSER TO THE WY BORDER MAY NOT SEE MUCH PCPN LATER THIS MORNING
THRU THE AFTN HOURS WHILE AREAS FM DENVER SOUTH TO THE PALMER DIVIDE
SEE THE BEST CHC. WITH STEEP LAPSE RATES THERE COULD BE SOME
ISOLD TSTMS AS WELL IN THE AFTN. ONE POTENTIAL ISSUE IS LYR OF DRY
AIR IN THE LOWER LEVELS AND HOW LONG IT WILL TAKE TO ERODE AS
THERE COULD BE QUITE A BIT OF VIRGA INITIALLY BEFORE SATURATION
OCCURS. MEANWHILE WET BULB ZEROS SUGGEST PCPN MAY FALL MOSTLY AS
SNOW AT LOWER ELEVATIONS WITH A MIX OVER THE FAR NERN PLAINS.
DEPENDING ON HOW THINGS EVOLVE COULD SEE AN INCH OR SO OVER THE
SRN AND WESTERN SUBURBS OF DENVER WITH SLIGHTLY HIGHER AMOUNTS
OVER THE PALMER DIVIDE. THE HRRR AND RAP HAVE NOT BEEN MUCH HELP
TONIGHT DUE TO HOUR TO HOUR INCONSISTENCIES WITH WITH REGARDS TO
PCPN POTENTIAL.

AS FOR HIGHS WILL KEEP READINGS MAINLY IN THE 40S OVER NERN CO
HOWEVER THE FAR NERN CORNER COULD RISE INTO THE LOWER 50S WHERE PCPN
POTENTIAL AND CLOUD COVER WILL BE LESS.

FOR TONIGHT PCPN SHOULD GRADUALLY END BY EARLY EVENING IN THE
MTNS...SRN FOOTHILLS AND ACROSS THE PALMER DIVIDE WITH CLEARING
SKIES OVERNIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM MDT WED MAR 25 2015

STRONG NORTHERLY FLOW ALOFT THURSDAY MORNING GIVES WAY TO
DECREASING NORTHWESTERLY FLOW ALOFT LATER THURSDAY THROUGH FRIDAY
NIGHT. AND UPPER RIDGE APPROACHING SLOWLY FROM THE WEST IS THE
CAUSE. THERE IS WEAK DOWNWARD SYNOPTIC SCALE ENERGY PROGGED FOR
THE CWA THURSDAY THROUGH FRIDAY NIGHT. THE BOUNDARY LAYER FLOW IS
DOWNSLOPING NORTHWESTERLY ON THURSDAY...THEN NORMAL PATTERNS
THURSDAY NIGHT. THERE IS WEAK NORTHWESTERLY DOWNSLOPING ON FRIDAY
THAN NORMAL DRAINAGE AGAIN FRIDAY NIGHT. FOR MOISTURE...THERE IS
SOME AROUND ON THURSDAY AND THURSDAY EVENING...THEN IT DRIES OUT
FOR THE REST OF THURSDAY NIGHT THROUGH FRIDAY NIGHT. THERE IS NO
CAPE PROGGED OVER THE CWA ALL FOUR PERIODS. THE QPF FIELDS SHOW
THAT THERE IS A TINY BIT OF MEASURABLE PRECIPITATION ONLY ON THE
GFS FOR LATE DAY THURSDAY. WILL GO WITH "SLIGHT CHANCE"S IN THE
MOUNTAINS FOR LATE DAY RAIN/SNOW ON THURSDAY ONLY. FOR
TEMPERATURES...THURSDAY`S HIGHS WARM UP 4-7 C OVER TODAY`S HIGHS.
FRIDAY`S READINGS ARE ANOTHER 3-6 C WARMER THAN THURSDAY`S. FOR
THE LATER DAYS...SATURDAY THROUGH TUESDAY...THE UPPER RIDGE IS
MOVING OVER COLORADO AND WEAKENING ON SATURDAY. THE ECMWF HAS A
VERY WEAK UPPER TROUGH ON SATURDAY NIGHT...THE GFS KEEPS RIDGING.
ON SUNDAY...THERE IS EITHER ZONAL FLOW OR NORTHWESTERLY FLOW
ALOFT...WITH A WEAK CLOSED LOW/TROUGH TO OUR SOUTHWEST. THIS
THING PUSHES EAST ON MONDAY...WITH MORE RIDGING AND WEAK ZONAL
FLOW ON TUESDAY. THE GFS HAS WAY MORE MID AND UPPER LEVEL
MOISTURE ALL FOUR DAYS COMPARED TO THE MUCH DRIER ECMWF. REALLY
THERE IS LITTLE GOING ON AND GFS HAS SOME MINOR MEASURABLE
PRECIPITATION HERE AND THERE WITH NOTHING ON THE ECMWF. WILL GO
WITH LITTLE TO NO POPS.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 350 AM MDT WED MAR 25 2015

THERE WILL BE A CHANCE OF SNOW SHOWERS IN THE 14Z THRU 21Z PERIOD WITH
THE BEST CHANCES STAYING MAINLY SOUTH OF DIA. WITH STEEP LAPSE
RATES CAN`T COMPLETELY RULE OUT AN ISOLD TSTM IN THE AFTN. ANY
SNOWFALL ACCUMULATION SHOULD STAY ON GRASSY AREAS AND BE AN INCH
OR LESS IN MOST PLACES. THE THREAT OF SNOW AT DIA SHOULD GRADUALLY
END BY 00Z. CEILINGS WITH THE PCPN MAY DROP DOWN TO AROUND 2500 FT
WITH VISBILITIES MOSTLY IN THE 3-5 RANGE UNLESS A HEAVIER SHOWER
MOVES ACROSS.

AS FOR WINDS THEY HAVE BECOME LIGHT SSE IN THE PAST FEW HOURS. A
CDFNT WAS ALREADY OVER CENTRAL WELD AND WILL MOVE ACROSS BEFORE
12Z. WINDS WILL PROBABLY SUBSIDE BY EARLY TO MID AFTN AND THEN
BECOME MORE NNW BY 21Z. BY EARLY EVENING WINDS WILL BE LIGHT NWLY
AND THEN WILL TRANSITION TO DRAINAGE AFTER 03Z.


&&

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

$$

SHORT TERM...RPK
LONG TERM...RJK
AVIATION...RPK



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