Severe Thunderstorm Warning 25, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
303 PM MDT SAT MAY 31 2008

.SHORT TERM...CUMULUS FIELDS CURRENTLY OVER THE EASTERN TWO-THIRDS
OF THE PLAINS AND OVER THE NORTHERN FOOTHILLS.  RADAR SHOWS SOME
CELLS OVER MORGAN...LOGAN...PHILLIPS...AND SEDGWICK COUNTIES WHICH
ARE PRODUCING LIGHT TO MODERATE SHOWERS.  THERE ARE EVEN A FEW
LIGHTNING STRIKES.  SURFACE OBSERVATIONS ARE SHOWING SOUTH TO
SOUTHEASTERLY WINDS OVER MOST OF THE PLAINS.  THE FLOW ALOFT IS DUE
WESTERLY.  THE ONLY 40S F DEW POINTS ARE RELEGATED TO THE NORTHEAST
CORNER.  MODELS HAVE THE UPPER RIDGE AXIS OVER THE FORECAST AREA
TONIGHT AND SUNDAY WITH WESTERLY FLOW ALOFT.  THE QG VERTICAL
VELOCITY FIELDS HAVE WEAK UPWARD MOTION OVER THE FORECAST AREA
TONIGHT AND SUNDAY.   THE BOUNDARY LAYER FLOW IS PROGGED TO BE
MAINLY SOUTHEASTERLY OVER THE PLAINS TONIGHT AND SUNDAY.  FOR
MOISTURE...BOTH MODELS HAVE QUITE A BIT OVER THE EASTERN THIRD OF
THE FORECAST AREA OVERNIGHT AND SUNDAY.  THE PRECIPITABLE WATER
VALUES ARE IN THE 0.90 TO 1.10 INCHES.  THIS IS OPPOSED TO THE HALF
INCH NUMBERS OVER THE FRONT RANGE PLAINS.  THE MOUNTAINS STAY PRETTY
DRY TONIGHT AND SUNDAY ON BOTH MODELS.  THE NAM HAS 40S AND 50S F
DEW POINTS OVER THE EASTERN PLAINS BY MID DAY SUNDAY.  THIS MODEL
HAS HAD A HISTORY OF NOT LOCATING THIS LOW LEVEL MOISTURE PROPERLY
OVER OUR FORECAST AREA.  SO I AM NOT SURE WHERE THE GOOD MOISTURE
WILL ACTUALLY END UP BY SUNDAY AFTERNOON?  BOTH MODELS HAVE A
SUBSTANTIAL THETA-E AXIS OVER THE PLAINS ON SUNDAY.  CAPE VALUES ARE
PRETTY DECENT...1000-2500 J/KG OVER ALL THE PLAINS AND FOOTHILLS
FROM MID-DAY ONWARD.  THE WIND PROFILE ON THE SOUNDINGS OVER THE
EASTERN PLAINS BY LATE DAY SUNDAY YIELDS SIGNIFICANT HELICITY VALUES
THERE.  LAPSE RATES ARE PRETTY STEEP OVER MOST OF THE FORECAST AREA
BY LATER IN THE AFTERNOON...THE EXCEPTION BEING THE EASTERN HALF OF
THE PLAINS...WHERE A DECENT CAP IS IN PLACE THROUGH 00Z LATER
AFTERNOON.  POPS HINGE ON WHERE THE MOISTURE GETS TO.  WELL SEE.
FOR TONIGHT...WILL GO WITH MINOR POPS FOR THE PLAINS...BEST FURTHER
EAST.  ON SUNDAY...WITH MOISTURE ISSUE AND CIN EXPECTED TO HANG ON
OVER THE EASTERN PLAINS...WILL CHANGE LITTLE AND LEAVE THE MINIMAL
POPS GOING.  FOR TEMPERATURES...SUNDAYS HIGHS LOOK TO BE 1-2 C
WARMER THAN CURRENT HIGHS.

.LONG TERM...LOW LEVEL MOISTURE WILL CONTINUE TO STREAM NORTHWARD
ACROSS EASTERN COLORADO TOMORROW EVENING.  WIND SHEAR IS VERY STRONG
AS WELL WITH 0-6KM HODOGRAPH LENGTH NEAR 35-40 M/S...WHICH WOULD
SUPPORT SUPERCELL AND SEVERE STORM DEVELOPMENT.  LOW LEVEL SHEAR IS
ALSO VERY STRONG WITH 0-3KM HELICITIES INCREASING TO OR ABOVE 300
M2/S2 OVER A GOOD CHUNK OF THE EASTERN PLAINS...AND A NARROW
CORRIDOR OF 0-1KM HELICITIES OF 100-200 M2/S2.  NAM USUALLY OVERDOES
THESE NUMBERS A BIT IN THE EVENING HOURS BUT THEY ARE STILL
INDICATIVE OF TORNADIC POTENTIAL WITH ANY OF THE STORMS.
HOWEVER...WITH THAT SAID...THERE IS ALSO POTENTIAL FOR THE AIRMASS
TO REMAIN CAPPED OFF WITH WARM MID LEVEL TEMPS AND SLIGHTLY COOLER
LOW LEVELS IN THE MOIST AIRMASS.  LOOKS LIKE AN ALL OR NOTHING
SETUP...BUT WILL HAVE TO MENTION THE THREAT OF SEVERE WEATHER OVER
THE EASTERN PLAINS FOR NOW GIVEN THE STRONG SHEAR.

MONDAYS WEATHER SHOULD BE A BIT MORE TRANQUIL AS LOW LEVEL MOISTURE
GETS SCOURED EAST OF THE AREA...BUT STILL ENOUGH HEAT AND
INSTABILITY TO MENTION A SLIGHT CHANCE OF STORMS ACROSS THE
FOOTHILLS/PLAINS.  NOT MUCH CHANGES FOR TUESDAY IN THE OVERALL
PATTERN...SO WILL KEEP THE WARM TEMPERATURES AND JUST A SLIGHT
CHANCE OF STORMS IN THE FORECAST.

BY WEDNESDAY...THE NEXT TROUGH IS ADVERTISED TO DIG INTO THE GREAT
BASIN WITH STRONG SOUTHWEST FLOW ALOFT.  LOW LEVEL MOISTURE IS ALSO
ADVERTISED TO INCREASE AGAIN ACROSS THE PLAINS WHICH WOULD RESULT IN
ANOTHER THREAT OF MORE ORGANIZED SEVERE WEATHER.  THE TROUGH SHOULD
MOVE PAST SOMETIME THURSDAY OR THURSDAY NIGHT WITH A RETURN TO DRY
AND WARMER WEATHER BY FRIDAY AND SATURDAY.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH SUNDAY
AFTERNOON...WHEN ISOLATED SHOWERS AND THUNDERSTORMS ARE FORECAST
AFTER 21Z.

&&

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

&&
RJK/BARJENBRUCH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1051 AM MDT SAT MAY 31 2008

COZ030>051-011200-
JACKSON COUNTY BELOW 9000 FEET-WEST JACKSON AND WEST GRAND
COUNTIES ABOVE 9000 FEET-GRAND AND SUMMIT COUNTIES BELOW 9000
FEET-SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-SOUTH AND SOUTHEAST
GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/GILPIN/CLEAR CREEK/
SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND
BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-JEFFERSON AND WEST
DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK
COUNTIES BELOW 9000 FEET-CENTRAL AND SOUTHEAST PARK COUNTY-LARIMER
COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-BOULDER AND JEFFERSON
COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY-NORTH DOUGLAS
COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/
EAST BROOMFIELD COUNTY-ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES
ABOVE 6000 FEET-NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD
COUNTY-MORGAN COUNTY-CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN
COUNTY-LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS
COUNTY-
1051 AM MDT SAT MAY 31 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED OVER THE FORECAST
AREA THIS AFTERNOON AND EVENING.  THE ALPINE AREAS CAN EXPECTED THE
ISOLATED STORMS AFTER 1 PM.  THE PLAINS CAN EXPECTED THEM AFTER 4
PM.  THE MAIN THREAT WITH THE STORMS WILL BE STRONG GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THERE WILL BE A GREATER RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHEAST PLAINS OF COLORADO SUNDAY AFTERNOON AND EVENING.  MOISTURE
IS EXPECTED TO INCREASE ACROSS THE PLAINS DURING THE DAY
SUNDAY...RESULTING IN CONSIDERABLY HIGHER INSTABILITY.  IN
ADDITION...WIND SHEAR IN THE ATMOSPHERE WILL BE STRONG...WHICH WOULD
AID THE DEVELOPMENT OF SEVERE THUNDERSTORMS.  AT THIS TIME...THE
GREATEST MOISTURE AND INSTABILITY IS EXPECTED TO SET UP IN AREAS
EAST OF A LINE FROM FORT COLLINS TO DENVER INTERNATIONAL AIRPORT TO
NEAR KIOWA.  IT SHOULD ALSO BE NOTED THAT A MID LEVEL CAP MAY
PREVENT STORM DEVELOPMENT ALTOGETHER...SO THIS WILL HAVE TO BE
MONITORED.  IF STORMS DO DEVELOP LATE SUNDAY AFTERNOON OR
EVENING...THEY WILL BE CAPABLE OF PRODUCING LARGE HAIL...DAMAGING
WINDS...AND TORNADOES.

FOR MONDAY THROUGH THURSDAY OF NEXT WEEK...THERE WILL BE A SLIGHT
CHANCE OF THUNDERSTORMS EACH DAY.  THE MAIN THREAT OF SEVERE
WEATHER DURING THIS TIME FRAME WOULD BE WEDNESDAY AFTERNOON AND
WEDNESDAY NIGHT AS A STRONGER STORM SYSTEM MOVES INTO THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

RJK/BARJENBRUCH