Winter Storm in Colorado, November 25 to 26, 2001

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
230 PM MST SUN NOV 25 2001

SHORT TERM:  CURRENT RADAR PICTURES AREA SHOWING SNOW ON THE BIG
INCREASE OVER THE SOUTHWEST FORECAST AREA AND UPSTREAM.  A SPOTTER
IN PARK COUNTY 5 MILES SOUTH OF HARTSEL HAD 2.0 INCHES OF SNOWFALL
IN A HALF HOUR.  GRIDS SHOW STRONG SYNOPTIC SCALE UPWARD FORCING
THROUGH ABOUT 03-06Z....REAL GOOD OVER PLAINS AT 00Z THIS EVENING.
CURRENT MSAS/LAPS DATA SHOWS THE SURFACE CYCLONE TO DEVELOP OVER THE
FAR SOUTHEAST CORNER OF COLORADO.  CURRENT OBSERVATIONS OVER THE OUR
PLAINS WIDESPREAD NORTHEAST/EASTERLY LOW LEVEL FLOW EVERYWHERE.
CROSS SECTIONS SHOW DECENT POTENTIAL INSTABILITY UNTIL MID EVENING.
SO WITH THAT UPSLOPE AROUND AND EXPECTED TO CONTINUE FOR A WHILE
ALONG WITH THE CURRENT RADAR/SATELLITE PICTURES...AND THE 18Z
MM5/MESOETA PRECIPITATION/SNOWFALL GRAPHICS...WILL PUT SOME LIKELY
SNOWS OVER THE PLAINS THROUGH ABOUT MID EVENING WITH MINIMAL
ACCUMULATIONS.  THE SYNOPTIC SCALE...GRIDS SHOW THE ASCENT DONE
ACROSS THE FORECAST AREA FROM WEST TO EAST AT 03-06Z.  THE UPPER
TROUGH AXIS IS OVER THE FAR EASTERN FORECAST AREA BY 06Z.  PRETTY
STRONG DOWNWARD FORCING IS EXPECTED BEHIND IT.  SO THATS WHEN THE
GOOD OROGRAPHICS KICK IN OVER THE MOUNTAINS...BUT THEN ITS
SUBSIDENT.  SNOW MODEL BARELY YIELDS SNOW ADVISORY AMOUNTS FROM THE
PERIOD 00Z THIS EVENING THROUGH 18Z MONDAY NOON TIME.  HOWEVER
STRONG WINDS ARE EXPECTED AFTER THE THOUGH PASSES AND BLOWING SNOW
WILL BE A PROBLEM.  THE CURRENT ADVISORY IS FINE...MAYBE IT MAY NEED
TO BE EXTENDED INTO MONDAY?   STRONG WINDS ARE CURRENTLY IN THE
FORECAST AND THAT LOOKS GOOD.  NO HIGHLIGHT FOR WIND AT THIS
TIME...BUT IT COULD GET CLOSE IN MANY AREAS.  ITS ONLY BEEN 31 F AT
THE BIG AIRPORT FOR THE HIGH SO FAR TODAY.  TEMPERATURE PROGS SHOW
A 1.5-4.0 C COOL OFF FOR 12Z LOWS...THEN A MORE COOLING FOR MONDAYS
HIGHS.          RJK

LONG TERM:  MON NGT THRU WED...MDLS KEEP BROAD UPR TROF OVR FCST
AREA THRU TUE NGT BFR UPR RDG BLDS OVR CNTRL RCKYS ON WED.  WITH
CANADIAN HI PRES AT SFC ALG WITH WK UPSLP FLO AGNST E SLP MTNS...AMS
WILL STAY QUITE COLD WITH SUM SNW FLURRYS ALG ERN SLPS.  WITH LOTS
OF PAC MSTR AND NWLY FLO AND COLD AIR ADVCTN ALF OROGRAPHIC SNW WILL
CONT MTNS THRU TUE BFR TAPERING OFF TUE NGT.  GUD DYNAMICS ALG WITH
UPWRD Q-G FORCING WILL ENHANCE SNWFALL ON MON NGT INTO TUE.  HWVR
SNW MDL AMTS WERE LIGHT DUE TO COLD TEMPS ALF.  WED WILL BRING GUD
WRM AIR ADVCTN ALF AND DRYING TO ALL OF AREA ALONG WITH WRMG TEMPS.
WILL GENLY COMPROMISE AMONGST WRMR NGM AND COOLER AVN MOS TEMP
GDNC.

IN XTNDD PRD...THU THRU SUN...MRF MOVES UPR TROF ACRS AREA BUT SFC
LO SYS WILL MOVE ACRS NRN GRT PLAINS...SO DRY AND WINDY OVR PLAINS
WITH CHC SNW MTNS THRU SAT.  WK UPR RDG FORMS OVR WRN U.S. ON SUN.
WILL MAKE NO CHANGS TO XTNDD AND ADD DAY 7.  MRF MOS TEMPS LUK OK.

GARD...WFO BOULDER

.DEN...SNOW AND BLOWING SNOW ADVISORY TONIGHT FOR ZONES 31/33/34.