Severe Thunderstorm Warning 183, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
300 PM MDT FRI JUL 24 2009

.SHORT TERM...STABLE HIGH PRESSURE WILL CONTINUE TO HOLD OVER THE
DESERT SOUTHWEST THROUGH SATURDAY AS A DEEP TROUGH OF LOW PRESSURE
SPINS OVER ONTARIO CAN. WITH PERSISTANT NORTHWEST FLOW OVER THE
NORTHERN HIGH PLAINS...A WEAK TROUGH AND ASSOCIATED COLD FRONT WILL
ENTER NORTHEAST COLO LATE TONIGHT WITH COOLER TEMPS EXPECTED FOR
SATURDAY. CURRENTLY...SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER
SW WYO THIS AFTN AND WILL LIKELY RIDE ALONG THE COLO BORDER THROUGH
THE EVE HOURS. SFC DEWPTS HAVE LOWER CONSIDERABLY TODAY ACROSS THE
CWA WITH THE HIGHEST DEWPTS HOLDING OVR EXTREME NE CORNER. WILL KEEP
ISOLD POPS GOING OVE THE AREA WITH THE BEST CHANCE FOR STORMS OVER
THE FAR NE PLAINS. DESPITE FAIRLY BENIGN FORCING FEATURES ALOFT...
COULD NOT RULE OUT AN ISOLD SEV STORM OVER FAR NE COLO LATE TGNT AS
COLD FRONT APPROACHES. THE VARIOUS SHORT TERM MDLS BRING THE FRONT
INTO THE CWA IN THE 09Z-12Z TIME FRAME AND SHLD INTIALLY ACT AS A
STABILIZING FEATURE OVERNIGHT AND FOR SATURDAY MORNING. BASED ON
CURRENT OBSERVATION ASSOC WITH THE 2-3MB HGT RISES OVR MT/WYO...
MOISTURE WILL BE AVAILABLE WITH THE FRONT. THIS COULD BE A SITUATION
WHERE THUNDERSTORM OUTFLOW NEAR THE STATE BORDER BLENDS IN WITH THE
ACTUALLY FRONTAL BOUNDARY ALLOWING FOR AN EARLIER ARRIVAL OF THE
ADVERTISED FRONT. AT ANY RATE...850-700MB LAYER SPEC HUMIDITIES RISE
APPROX 5 G/KG CWA WIDE AND WITH EASTERLY UPSLOPE FLOW EXPECTED FOR
MOST OF SAT...BEST CHANCE FOR THUNDERSTORMS INITIATION WILL BE OVER
THE HIGH COUNTRY. FCST SOUNDINGS SHOW CONSIDERABLE STABILITY IN THE
LOWER AND MID LEVELS AFTER FRONT PASSAGE...THEREFORE WILL KEEP THE
PLAINS IN THE ISOLD CATEGORY. WILL BUMP UP POPS FOR THE
MTNS...FOOTHILLS AND URBAN CORR DUE TO INCREASED MOISTURE COMBINED
WITH EARLIER HEATING. ATTM...WILL EXPECT STRATUS WITH THE FRONT
ESPECIALLY IN AND NEAR THE FOOTHILLS AND COULD TAKE A FEW HOURS BURN
OFF. GUIDANCE TEMPS SEEM MORE IN LINE FOR TGNT AND SAT...SO WILL
EXPECT TEMPS 9-13 DEGF COOLER THAN TDYS.

.LONG TERM...THE LONG TERM WILL BE CHARACTERIZED BY COOLER AND
WETTER WEATHER THROUGH NEXT WEEK. FLOW ALOFT WILL REMAIN MOSTLY
NORTHWEST THROUGH THE PERIOD AS A LONG WAVE TROUGH REMAINS NORTH OF
THE GREAT LAKES REGION AND THE UPPER HIGH REMAINS TO THE SOUTHWEST.
THIS PATTERN WILL BRING COOLER CANADIAN AIR AND SEVERAL SHORTWAVES
ALONG WITH MOISTURE FROM THE PACIFIC AND SOUTHWEST WILL KEEP POPS UP
EACH DAY AS WELL.

SHOWERS AND THUNDERSTORMS WILL CONTINUE SATURDAY EVENING IN THE
MOIST POST FRONTAL AIRMASS...MAINLY OVER THE FOOTHILLS AND PALMER
DIVIDE WHERE THE HIGHEST CAPE VALUES WILL RESIDE. SUNDAY BE A BIT OF
A REPEAT OF SATURDAY...HOWEVER WITH AN INCREASE IN SHEAR VALUES.
PW VALUES ARE PROGGED TO CLIMB AGAIN TO AROUND 1.25-1.5 INCHES AND
CAPES WILL RANGE FROM 1300-1900 J/KG WITH THE HIGHER VALUES OVER THE
FOOTHILLS AND PALMER DIVIDE AGAIN.  ISOLATED SEVERE STORMS ARE
POSSIBLE AGAIN ON SUNDAY...WITH CONDITIONS A LITTLE BETTER THAN
SATURDAY.

MONDAY THROUGH WEDNESDAY LOOKS TO BE OUR COOLEST AND WETTEST PART OF
THE FORECAST PERIOD AS A STRONG TROUGH WILL DROP OUT OF THE
NORTHWEST AND MOVE INTO THE CWFA BRINGING WITH IT A FEW COLD FRONTS.
BUMPED THE POPS UP FURTHER OVER THE ENTIRE AREA FOR TUESDAY WHEN THE
STRONG FRONT PUSHES SOUTH AND THE UPPER TROUGH PASSES OVER HEAD LATE
THAT NIGHT. GFS AND ECMWF CONTINUE TO SHOW UNSEASONABLY COLD
TEMPERATURES SLIDING DOWN TUESDAY NIGHT. BOTH ARE SHOWING 700 MB
TEMPERATURES OF 2-4 DEGREES C OVER THE NORTHEASTERN PART OF THE
STATE TUESDAY NIGHT...HAVE INTRODUCED A SLIGHT CHANCE OF FLURRIES AT
THE HIGHEST ELEVATIONS.  THE COOLER WET PATTERN LOOKS TO CONTINUE
THROUGH THE REST OF THE WEEK AS THE UPPER LEVEL PATTERN WILL REMAIN
IN PLACE. AS THE LAST FORECASTER NOTED...WITH A PERSISTENT PATTERN
IN PLACE THIS MONSOON SEASON MAY NEED TO BE RENAMED THE CANADIAN
MONSOON.

&&

.AVIATION...UPPER LEVEL HIGH PRESSURE WILL CONTINUE TO DOMINATE THE
REGION THROUGH SATURDAY WITH A COLD FRONT EXPECTED TO ENTER
NORTHEAST COLORADO AFTER 09Z. LOW CEILINGS CAN BE EXPECTED FROM 09Z
THROUGH 15Z. THUNDERSTORMS WILL DEVELOP OVER THE HIGHER TERRAIN
AFTER 18Z AND MOVE ON THE PLAINS DURING THE LATE AFTERNOON HOURS.

&&

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

FREDIN/KRIEDERMAN

HAZARDOUS WEATHER OUTLOOK...DELAYED
NATIONAL WEATHER SERVICE DENVER CO
1053 AM MDT FRI JUL 24 2009

COZ030>051-251200-
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-
1053 AM MDT FRI JUL 24 2009

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

.DAY ONE...TODAY AND TONIGHT

STABLE HIGH PRESSURE WILL CONTINUE TO DOMINATE THE REGION TODAY WITH
THE LOWER LEVELS OF THE ATMOSPHERE REMAINING FAIRLY DRY. A COLD
FRONT WILL MOVE INTO NORTHEAST COLORADO AFTER 9PM. THERE WILL BE A
SLIGHT CHANCE FOR THUNDERSTORMS ACROSS THE AREA THIS AFTERNOON AND
EARLY EVENING. THUNDERSTORMS EXPECTED TO BE HIGH BASED OVER THE HIGH
COUNTRY...FOOTHILLS AND URBAN CORRIDOR WITH GUSTY WINDS BEING THE
PRIMARY THREAT. AFTER 9PM...A FEW THUNDERSTORMS COULD BE SEVERE WITH
HAIL AND HEAVY RAIN POSSIBLE MAINLY OVER EXTREME NORTHEAST COLORADO.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A COOLER AND WETTER PATTERN WILL BE IN PLACE FOR NORTHEAST COLORADO
THROUGH THE PERIOD WITH NORTHWESTERLY FLOW ALOFT AND A SERIES OF
DISTURBANCES EXPECTED TO MOVE THROUGH THE REGION.  THIS WEEKEND WILL
SEE A CHANCE FOR THUNDERSTORMS EACH DAY WITH A FEW POSSIBLE SEVERE
STORMS...A GREATER CHANCE SUNDAY AND MONDAY. THE PATTERN OF
AFTERNOON AND EVENING THUNDERSTORMS WILL CONTINUE INTO NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

FREDIN/KRIEDERMAN