NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NWS DENVER COLORADO
AFDDEN 315 PM MDT SUN APR 8 2001
SHORT TERM DISCUSSION: SWLY FLOW ALOFT ACRS THE FCST AREA WL KEEP
THE PLAINS GENERALLY DRY. SOME SHOWER ACTIVITY ON THE LEADING EDGE
OF THE UPSTREAM TROF HAS BEEN MOVING OVR THE HIGH COUNTRY AND
LARIMER COUNTY. ACARS SOUNDINGS AT DEN INTL AIRPT SHOW THAT AN
INVERSION IS STILL IN PLACE ARND 16KFT. THIS SHUD LIMIT THE SHOWER
DVLPMNT THRU THE REST OF THE AFTN. LATER TONIGHT...SKIES ON THE
PLAINS WL REMAIN MSTLY CLEAR...ALLOWING TEMPS TO DROP DOWN TO THE
LOWER AND MID 30S. AFTN LAPS SFC ANALYSIS SHOWS A CLOSED LOW ASSOCD
WITH THE ERN CO LEE TROF AND HIGHER PRESSURE IN WRN NEBRASKA. THE
WEAK SFC WIND PATTRN WL ALLOW STRATUS TO RE-DVLP TONIGHT AND WORK
ITS WAY UP THE S PLATTE VALLEY. THIS SCENARIO IS VERY SIMLR TO WHAT
WE SAW EARLIER THIS MRNG WHEN ONLY THE PALMER DIVIDE WAS SPARED FROM
MRNG STRATUS AND FOG. KDRBY
LONG TERM DISCUSSION: BROAD UPPER TROUGH AND UPPER LOW TO REMAIN
WEST OF COLORADO MONDAY...THEN SLIDE INTO GREAT BASIN BY 18Z
TUESDAY. MODELS IN FAIRLY GOOD AGREEMENT THROUGH TUESDAY.
ON MONDAY...SHORTWAVE RIDGE DEVELOPS OVER CWA AS UPPER TROUGH DIGS
ALONG WEST COAST. CROSS SECTIONS AND DIV-Q FIELDS INDICATE A
SUBSIDENT AIRMASS WHICH SHOULD KEEP ANY PRECIPITATION FROM
DEVELOPING. WILL KEEP CWA DRY DESPITE AMPLE MOISTURE SHOWN OVER
MOUNTAINS ON ETA CROSS SECTIONS. MOISTURE SHOULD BEGIN TO INCREASE
OVER AREA MONDAY NIGHT AS UPPER TROUGH/UPPER LOW BEGINS ITS TREK
TOWARD COLORADO. SOME SNOW SHOWERS CAN BE EXPECTED OVER MOUNTAINS
AS DYNAMICS FROM SYSTEM NOSES INTO WESTERN SECTIONS OF CWA. GRIDDED
WIND FIELDS INDICATE FRONT TO MOVE ACROSS NORTHEAST PLAINS AROUND
MIDNIGHT.
FOR TUESDAY...MOUNTAIN SNOWS SHOULD CONTINUE...BUT SOUTHWEST FLOW
ALOFT NOT CONDUCIVE FOR ANYTHING WIDESPREAD. THIS COULD CHANGE IF
UPPER LOW AND TROUGH EJECT NORTHEAST QUICKER THAN FORECAST. FOR THE
PLAINS...CROSS SECTIONS INDICATE FAIRLY DEEP MOISTURE LAYER DURING
THE AFTERNOON. LAPSE RATES BECOME RESPECTABLE...IN THE 9 C/KM RANGE
BY 00Z WEDNESDAY. DYNAMICS FROM SYSTEM SPREAD OVER THE AREA. SHEAR
PROFILE ALSO RATHER IMPRESSIVE...WITH SOUTHEASTERLIES AT THE SURFACE
TURNING TO SOUTHWESTERLIES AROUND 500 MB. THE AFTERNOON/EVENING
HOURS COULD BE INTERESTING...THUNDERSTORM-WISE. FOR TUESDAY
NIGHT...GRIDDED WIND FIELDS SHOW STRENGTHENING UPSLOPE FLOW OVER
NORTHEAST AS SURFACE LOW BEGINS TO DEVELOP EAST OF ROCKIES. RAIN
SHOULD HAVE SOME SNOW MIXED IN AS TEMPERATURES DROP INTO THE 30S.
SNOW OVER MOUNTAINS COULD BEGIN TO INCREASE IN COVERAGE AS DYNAMICS
IMPROVE.
FOR EXTENDED PERIOD...LATEST MODELS DON'T DEVIATE MUCH FROM PREVIOUS
RUNS. UPPER LOW SHOULD MOVE NORTHEAST ACROSS COLORADO WEDNESDAY
GOOD INSTABILITY...COLD AIR AND MOISTURE EQUATE TO THE CHANCE OF
SHOWERS CWA-WIDE. IF SURFACE LOW MOVES NORTHEAST SLOWER THAN MRF
AND AVN INDICATE...NORTHEAST COLORADO...ESPECIALLY FOOTHILLS...
SHOULD SEE A GOOD SHOT OF UPSLOPE. QUESTIONS ARE HOW COLD
TEMPERATURES WILL GET...AND WILL THEY BE COLD ENOUGH FOR ALL SNOW.
WILL LEAVE CURRENT WORDING OF RAIN IN DAY AND RAIN/SNOW MIX AT
NIGHT. CONDITIONS SHOULD IMPROVE THURSDAY AS THE LOW EXISTS AREA
AND SHORTWAVE RIDGE REESTABLISHES ITSELF. NEXT TROFPA EXPECTED
FRIDAY INTO SATURDAY... FOR ANOTHER ROUND OF PRECIPITATION. A REALM
OF UNCERTAINTY ABOUNDS ASSOCIATED WITH THE MOVEMENT OF THIS TROUGH.
MRF HAS TROUGH EAST OF CWA BY 12Z SAT...WHICH POINTS TO A DRY DAY.
WILL KEEP THE CHANCE OF PRECIPITATION FOR NOW. SUNDAY LOOKS TO BE
THE DRY DAY AS THE MODELS INDICATE RIDGING. D-L
.DEN...NONE.