Heavy Snow in Colorado, March 24, 2002

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
230 AM MST SUN MAR 24 2002

SHORT TERM DISCUSSION: WK CDFNT HAS SWEPT THRU THE ERN PLAINS THIS
MRNG, BUT THE EFFECT OF THIS HAS BEEN NEGLIGIBLE SO FAR.  WNDS AT
THE SFC/BNDRY LYR HAV TURNED NELY, BUT LWR ATM RMNS QUITE DRY.  DWPT
DEPRESSIONS ARE STILL 5-8 DEGREES ACRS THE PLAINS...3-5 IN THE URBAN
CORRIDOR, SO WK UPSLOPE ISNT MANAGING TO POOL MUCH IN THE WAY OF
MSTR THIS MRNG.  STRATUS HAS THUS NOT DVLPD ANYWHERE, CONTRARY TO
00Z MM5 (06Z RUN NOT AVBL ATTM).  WILL STICK CLOSER TO THE MESOETA
FOR THE SHORT TERM FCST.

OVERALL, THE UPCOMING SYS CAN BE BEST DESCRIBED AS DISORGANIZED.  A
NICE JET LIES TO OUR S IN NEX MEX, WHILE THE CNTR OF COLDEST H5 AIR
SEEMS TO BE OVR SRN NV.  AS THE BROAD UPR TROF MOVS THRU TDY AND
TNGT, BY FAR THE BEST DYNAMICAL SUPPORT FOR PCPN WL RMN TO OUR S.
MESOETA HAS A GOOD DEPICTION OF FRONTOGENESIS DVLPG ALG SRN FLANK OF
UPR TROF WELL TO OUR SOUTH THIS AFTN.  MEANWHILE, A REINFORCING SFC
CDFNT WL SWEEP THRU THE PLAINS LT THIS AFTN/THIS EVENING.  THIS WL
CAUSE A LTL BTR UPSLOPE, BUT NOTHING TOO IMPRESSIVE. SO AS A RESULT,
THIS SYS WL BE LEFT TO RELY ON INSTABILITY AND DP MSTR TO PRODUCE
PCPN IN OUR AREA.  ATM WL BCM INCRLY UNSTBL THIS AFTN AND EVENING
WITH FAIRLY STEEP LAPSE RATES AFT 00Z WHEN CD AIR ALF ARRIVES.  UPR
WNDS WL SHIFT TO THE NW WHICH IS GNRLLY MORE FVRBL FOR SNOW IN OUR
AREA.

LOOKING AT THE MDLS QPF, MESOETA DOESNT HAV MUCH SNOWFALL DVLPG
UNTIL PD 2 WHEN THE STGR UPSLOPE DVLPS.  ALTHO MOST OF THE ELEMENTS
WL BE OUT OF PHASE DURING THIS PASSAGE OF THIS SYS, THERE WL BE A
BRIEF PD OF THERMODYNAMIC INSTABILITY ALG WITH UPSLOPE FLOW ARND
00Z.  ATTM, IT LOOKS LIKE THE BEST PD OF ACCUM SNOW WL BE FM
22Z-06Z. WL TRIM BACK ON THE SNOW TDY TO REFLECT A LTL LATER
EVOLUTION OF THIS STORM.  SNOW AMTS WL BE PRETTY LGT...PERHAPS 2-5
TOTAL MTNS...1-3 FOR THE PALMER DVD...AND AN INCH OR SO FOR THE
METRO. NO HILITES NEEDED 46

LONG TERM DISCUSSION:  THE WEAK AND DISORGANIZED UPPER LOW WILL
TRACK ACROSS SRN CO DURING THE DAY MONDAY. THE STRONGEST UPWARD
FORCING WILL REMAIN ACROSS SRN CO THRU MUCH OF THE DAY. THEN AS THE
SYSTEM MOVES INTO THE CENTRAL PLAINS...SUBSIDENCE MOVES OVERHEAD BY
AFTN WHILE LOW LVL FLOW SHIFTING SE-S. THIS WILL BE A GENERAL
DOWNSLOPE FLOW ACROSS THE URBAN COORIDOR...AND SHOULD END MUCH OF
THE PRECIP DURING THE MID MORNING HOURS WITH PARTIAL CLEARING IN THE
AFTN. WILL BUMP UP POPS A TAD FOR EARLY MON MORNING ACROSS SRN
SXNS...INCL PALMER DIVIDE/SRN FOOHTILLS DUE TO CLOSER PROXIMITY TO
UPPER LOW AND STRONGER UPWARD FORCING.

NW FLOW PATTERN THEN SETS UP THRU MID WEEK WITH A FEW MINOR
DISTURBANCES TRACKING ACROSS THE NRN PLAIN STATES. THESE MAY CLIP
NERN CO...BUT STILL LOOKS LIKE A DRY FCST WITH A GENERAL WARMING
TREND.

LOOKS LIKE NEXT FORECAST PROBLEM WILL BE TRACK OF NEXT CLOSED LOW
COMING IN OFF SRN CA BY LATE IN THE WEEK. LONG RANGE MODELS STILL
QUITE UNCERTAIN ABOUT TIMING AND POSITION OF LOW COMING INLAND
ACROSS SRN CA. CANADIANS HAVE LOW ACROSS SW CO BY 00Z SAT...WITH
MRF POSITION ACROSS LAS VEGAS AND THE NOGAPS SHOWING A MORE OPEN
WAVE ACROSS AZ. SUSPECT AN EVEN SLOWER MOVEMENT MAY BE NEEDED WITH
THIS TYPE OF CUTOFF AND NOT MUCH IN THE WAY OF A KICKER SEEN
UPSTREAM. NEW AVN IS MUCH SLOWER THAN LAST NIGHTS MRF. HENCE...NO
CHANGES TO EXTENDED FORECAST. ENTREKIN

.DEN...NONE.

COZ030>051-242000-

HAZARDOUS WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1100 AM MST SUN MAR 24 2002

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE  BOULDER     BROOMFIELD  CLEAR CREEK  DENVER
DOUGLAS   ELBERT    GILPIN      GRAND       JACKSON      JEFFERSON
LARIMER   LINCOLN   LOGAN       MORGAN      PARK         PHILLIPS
SEDGWICK  SUMMIT    WASHINGTON  WELD

SYNOPSIS:  A MOIST AND UNSTABLE AIRMASS WILL ALLOW FOR SNOW SHOWERS
TO INCREASE ACROSS THE NORTHEAST COLORADO AS AN UPPER LEVEL TROUGH
MOVES ACROSS NORTHERN COLORADO THIS AFTERNOON AND EVENING.  IN THE
MOUNTAINS...FOOTHILLS AND ALONG THE PALMER DIVIDE SOUTH OF DENVER
...TOTAL ACCUMULATIONS THROUGH TONIGHT MAY RANGE FROM 2 TO 5 INCHES.
ALONG THE I-76 AND I-70 CORRIDORS EAST OF DENVER...TOTAL SNOWFALL
ACCUMULATIONS WILL RANGE FROM 2 TO 4 INCHES...WITH LESSER AMOUNTS
EXPECTED ELSEWHERE.

OUTLOOK FOR MONDAY...MOSTLY CLOUDY AND CONTINUED COLD WITH A CHANCE
OF SNOW...MAINLY IN THE MORNING.

COOPER