Flash Flood Warning 3, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
240 PM MDT MON MAY 3 1999

CONCERNING THE FLOODING...WILL KEEP FLOOD WARNINGS GOING TONIGHT FOR
THE SOUTH PLATTE EAST OF GREELEY IN WELD COUNTY...AND FOR THE SOUTH
PLATTE IN MORGAN COUNTY TONIGHT AND TUESDAY.

SATELLITE/RADAR PICTURES INDICATING PLENTY OF CONVECTION TO OUR WEST
IN THE TROUGH AXIS.  LOCAL RADAR SHOWING SOME SHOWERS DEVELOPING IN
THE FOOTHILLS AND MOUNTAINS AT THIS TIME.  THE MOUNTAIN WAVE
SIGNATURE IS STILL APPARENT OVER FOOTHILL AREAS OF JEFFERSON AND
DOUGLAS COUNTIES.  OVER THE PLAINS...STRONG LOW LEVEL SOUTHWESTERLY
FLOW CONTINUES WITH NOT GREAT LOW LEVEL MOISTURE AT PRESENT TIME.
WILL KEEP SOME SHOWERS IN THE FORECAST OVERNIGHT WITH TROUGH AXIS
AND FRONT PROVIDING SOME LIFT.

UPPER TROUGH AXIS GETS INTO THE WESTERN FORECAST AREA AROUND 06Z
TONIGHT...THEN FINALLY GETS EAST OF THE NORTHEAST CORNER BY 00Z
TUESDAY AFTERNOON.  DECENT Q-G ASCENT NOTED IN THE GRIDS THROUGH THE
NIGHT TONIGHT...WITH AMPLE DOWNWARD FORCING PROGGED BY TUESDAY
AFTERNOON INTO THE EVENING.  CROSS SECTIONS ARE SHOWING VERY STEEP
LAPSE RATES AND DECENT POTENTIAL INSTABILITY TONIGHT THROUGH TUESDAY
...WITH COLD AIR OF THE TROUGH AXIS OVER US.  BY TUESDAY NIGHT AND
WEDNESDAY SOME WARMING ALOFT PUTS THE KIBOSH ON THIS.  FORECAST
SOUNDINGS ARE NOT VERY EXCITING AS FAR AS STRONG CONVECTION GOES
DURING ANY PERIOD.  THE BIG WEATHER WILL BE SNOW IN THE ALPINE
AREAS.  THIS EVENING YOU HAVE THE SYNOPTIC SCALE LIFT...INSTABILITY
...AND PLENTY OF MOISTURE...BY EARLY TUESDAY AND FOR THE REST OF THE
DAY YOU HAVE STRONG OROGRAPHIC FLOW WITH A FAVORABLE DIRECTION...
STRONG INSTABILITY...AND STILL PLENTY OF MOISTURE.  THE SNOW MODEL
GIVES PLENTY OF SNOW TO WARRANT A WARNING...ESPECIALLY WITH HOW COLD
THE 700 MB TEMPERATURES GET.  BY TUESDAY NIGHT INTO WEDNESDAY THE
UPPER FLOW GETS NEARLY DUE NORTHERLY...BUT THE MOISTURE DECREASES
AND THAT WARMING ALOFT COMMENCES.  THE WINDS WILL BE PRETTY
SUBSTANTIAL IN ALL AREAS AS THE TROUGH AXIS MOVES EAST...BUT NOT TO
CONCERNED WITH A WIND EVENT FROM A MOUNTAIN WAVE.  THE MOUNTAIN WAVE
SET UP IS NOT GREAT WITH A POOR CROSS BARRIER COMPONENT AND A VERY
POOR STABILITY PROFILE.  THE TEMPERATURE/THICKNESS GRIDS ARE SHOWING
DECENT COOLING BOTH TUESDAY AND WEDNESDAY.

IN THE EXTENDED...STRONG NORTHERLY FLOW ALOFT FOR THURSDAY...WITH
WEAKENING NORTHWESTERLY FLOW ALOFT FRIDAY...AND RIDGING ON SATURDAY.
RJK

.DEN...FLOOD WARNING TONIGHT...ZONES 43.
    ...FLOOD WARNING TONIGHT AND TUESDAY...ZONE 44.
    ...WINTER STORM WARNING TONIGHT...ZONES 33/34.

COZ030-032>050-040600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1115 AM MDT   MONDAY   MAY 3 1999

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

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

SYNOPSIS:  RAIN FROM THE PAST FEW DAYS CONTINUES TO CAUSE RUNOFF
PROBLEMS ALONG THE SOUTH PLATTE AS WELL AS SEVERAL RIVERS AND
STREAMS FEEDING INTO THE SOUTH PLATTE RIVER TODAY.  SEVERAL FLOOD
AND FLASH FLOOD WARNINGS ARE IN EFFECT FOR WELD AND MORGAN COUNTIES
TODAY.

IN ADDITION TO THE RUNOFF PROBLEMS...ANOTHER SPRING STORM IS HEADED
FOR COLORADO.  HEAVY SNOW IS EXPECTED TO DEVELOP IN THE NORTHERN
MOUNTAINS...ESPECIALLY ABOVE 9500 FEET...WITH 8 TO 14 INCHES BY
TUESDAY MORNING.

IN THE NORTHEAST PLAINS...SCATTERED RAIN SHOWERS ALONG WITH A FEW
THUNDERSTORMS WILL DEVELOP LATE THIS AFTERNOON AND CONTINUE TONIGHT.
THE SHOWERS ARE EXPECTED TO DIMINISH BY LATE TONIGHT AS A STRONG
DOWNSLOPE FLOW DEVELOPS IN THE WAKE OF THIS STORM SYSTEM.

END...COOPER...WSFO DENVER