Hail in Colorado, June 17, 2009

AREA FORECAST DISCUSSION...CORRECTION TO DATE
NATIONAL WEATHER SERVICE DENVER CO
315 PM MDT WED JUN 17 2009

.SHORT TERM...SEVERE WEATHER POTENTIAL INCREASING AT THIS HOUR
ACROSS THE NORTHEAST PLAINS OF COLORADO. SPC HAS ISSUED A TORNADO
WATCH FOR NORTHEAST AND EAST CENTRAL COLORADO NOW UNTIL 04Z/
TONIGHT. SEVERAL FACTORS COMING TOGETHER DURING THE NEXT FEW
HOURS...NAMELY INCREASING BNDRY LAYER MOISTURE...STEEP SFC-600 MB
LAPSE RATES...IMPROVING 0-6KM SHEAR PROFILE WITH INCREASING SELY
LOW-LEVEL FLOW AND A +90KT SWLY JET SEGMENT PASSING OVERHEAD. FOCUS
FOR STORM DEVELOPMENT NEXT COUPLE OF HOURS WILL BE ALONG A
PSEUDO-DRY LINE CREEPING NWRD OFF THE PALMER DIVIDE. SOUTH OF THIS
BNDRY SFC DEWPTS IN THE LOWER/MID 40S...NORTH OF IT MID/UPPER 50S.
NEW STORM CELLS FIRING JUST SOUTH OF DENVER ALONG THE WESTERN END OF
THIS BNDRY IN AN AREA OF DECENT LOW-LEVEL SHEAR. STILL SOME QUESTION
AS TO WHEN DEEP CONVECTION WILL REALLY GET GOING. Q-G VERTICAL
VELOCITY FIELDS INDICATE WEAK DOWNWARD MOTION OVER NERN COLORADO AS
OF 21Z WITH HINTS OF A CAP AROUND 600MBS ON FCST SOUNDINGS. WOULD
EXPLAIN THE LACK OF CLOUDS AND CONVECTIVE DEVELOPMENT EAST OF THE
I-25 CORRIDOR AT THIS HOUR. SUSPECT ONLY A MATTER OF TIME WHEN CAP
WILL BREAK AND STORMS BEGIN FIRING ON THIS NWRD MOVING BNDRY. COULD
SEE A FEW STORMS OVER AND NEAR THE URBAN CORRIDOR GOING SEVERE WITH
LARGE HAIL AND STRONG DAMAGING WINDS MAIN THREAT.

MODELS SHOW THIS BNDRY PROPAGATING SLOWLY N/NEWRD THRU THE I-25
URBAN CORRIDOR AND ACROSS SRN PORTIONS OF THE CWFA THRU 00Z. BUT
IT/S PROBABLY NOT UNTIL THIS BNDRY STARTS INTERACTING WITH THE
HIGHER DEWPTS AND STEEPER LAPSE RATES FARTHER OUT ON THE PLAINS.
PASSING JET WILL FURTHER ENHANCE THE LIFT PRODUCED ON THIS ADVANCING
SFC BNDRY. BUT IT/S ACROSS THE FAR NERN CORNER OF THE STATE WHERE
SEVERE WEATHER RISK AT ITS HIGHEST. MODEL CAPES IN THE 2500 TO 3800
J/KG RANGE THIS EVENING. SHEAR ALSO MUCH BETTER OUT THERE. LARGE
DAMAGING HAIL AND ISOLATED TORNADOES A GOOD BET OUT THERE. SHOULD
SEE A QUICK END TO STORMS ALONG THE FRONT RANGE THIS EVENING ONCE
THE DRY-LINE BNDRY MOVES EAST. HOWEVER...STORMS...SOME SEVERE...
COULD LINGER FOR MOST OF THE NIGHT ACROSS THE FAR NERN CORNER OF THE
STATE.

ON THURSDAY...MODELS CONTINUE TO SHOW AN UPPER LEVEL TROUGH AND AN
ACCOMPANYING COLD FRONT MOVING ACROSS THE FCST AREA LATE IN THE DAY.
AHEAD OF THIS SYSTEM...ATMOSPHERE STILL LOOKS MOIST AND UNSTABLE
WITH A STRONG SW-NE JET OVERHEAD. DAY EXPECTED TO START OUT UNDER
SCATTERED CLOUDINESS WITH PATCHY FOG ACROSS THE NERN CORNER. THEN
COLD FRONT MOVES DOWN OFF THE CHEYENNE RIDGE AROUND THE NOON
HOUR...AND ACROSS THE NERN PLAINS DURING THE AFTERNOON PRODUCING
THUNDERSTORMS ALONG THE WAY. HAIL PROBABLY THE BIGGEST THREAT
WITH THESE STORMS. MAY SEE A FEW STORMS GO SEVERE OUT ACROSS THE
NERN CORNER LATE IN THE DAY WHERE ATMOSPHERE WILL BE A BIT MORE
UNSTABLE. SINCE FRONTAL PASSAGE NOT ANTICIPATED UNTIL SOMETIME
DURING THE AFTERNOON...SUSPECT HIGH TEMPS WILL ONLY BE A FEW DEGS
LOWER THAN THOSE OBSERVED TODAY.

.LONG TERM...SHORTWAVE AND ANY ASSOCIATED THUNDERSTORMS WILL TAPER
OFF THURSDAY EVENING...POSSIBLY LINGERING ON THE EASTERN BORDER
LATE. PRETTY DECENT SUBSIDENCE ON FRIDAY WITH AN INVERSION AROUND
500 MB...THEN MOISTURE WILL COME UP FROM THE NORTH BUT IN A FAIRLY
STABLE ENVIRONMENT. MODELS ARE SHOWING MORE MOISTURE AND WEAK LIFT
ON SATURDAY...THOUGH THE ECMWF REMAINS FURTHER WEST WITH THE WAVE
LIFTING NORTHWARD AND IS LESS MOIST. NAM/GFS SOLUTIONS WIND UP WITH
A FAIRLY MOIST BUT ONLY SLIGHTLY UNSTABLE ENVIRONMENT...AND PRETTY
DECENT WIND SHEAR. INSTEAD OF LOOKING WARM AND FAIRLY DRY...THIS DAY
IS LOOKING MORE LIKE A LATE DAY CONVECTIVE EVENT. CLOUD COVER MAY
HOLD TEMPERATURES DOWN ENOUGH TO ROB THIS DAY OF ITS POTENTIAL
HOWEVER. ONLY SLIGHTLY BUMPED UP POPS BUT LOWERED HIGHS FOR SATURDAY.

ON SUNDAY MODELS ARE SHOWING THE RIDGING/WARMING/DRYING BEHIND THE
WAVE...SO NOW WE WILL SHOW THIS AS THE WARMEST DAY. MINOR VARIATIONS
AFTER THAT BUT GENERALLY SEASONAL TEMPERATURES AND POPS...STILL
HEADED FOR MORE SUMMERLIKE WEATHER.

&&

.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS IN THE DENVER AREA
THROUGH 02Z. A FEW STORMS MAY PRODUCE LARGE HAIL...WIND GUSTS TO
40KT AND HEAVY RAINFALL. MAY EVEN SEE A STORM OR TWO PRODUCE A
FUNNEL CLOUD OR BRIEF TORNADO. TORNADO WATCH IN EFFECT UNTIL 10 PM
MDT THIS EVENING. VISIBILITIES AS LOW AS 3 MILES WITH LATE AFTERNOON
/EARLY EVENING STORMS. IMPROVING CONDITIONS EXPECTED IN THE DENVER
AREA AFTER 9 PM MDT. ALTHOUGH MAY SEE PATCHY FOG FORMING TOWARD
SUNRISE WHICH COULD BRIEFLY REDUCE VISIBILITIES AT DENVER INTL
AIRPORT TO LESS THAN A MILE.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...TORNADO WATCH IN EFFECT FOR
NORTHEAST AND EAST CENTRAL COLORADO UNTIL 04Z/TONIGHT.

BAKER/GIMMESTAD

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DENVER CO
147 PM MDT WED JUN 17 2009

COZ030>051-181200-
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-
147 PM MDT WED JUN 17 2009

...SLIGHT RISK OF SEVERE THUNDERSTORMS LATER TODAY ACROSS PORTIONS
OF NORTHEAST OF COLORADO...

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

.DAY ONE...TODAY AND TONIGHT

CONDITIONS ARE EXPECTED TO COME TOGETHER TO PRODUCE SEVERE WEATHER
ON THE PLAINS OF NORTHEAST PLAINS OF COLORADO LATER THIS AFTERNOON.
AN INCREASINGLY MOIST AND VERY UNSTABLE ATMOSPHERE WILL COMBINE WITH
STRENGTHENING SOUTHEASTERLY LOW-LEVEL WINDS TO PRODUCE ISOLATED
SUPERCELL THUNDERSTORMS. STORMS DEVELOPING EAST OF A FORT MORGAN TO
BURLINGTON LINE AFTER 4 PM WILL BE CAPABLE OF HAIL UP TO 2 INCHES IN
DIAMETER...DAMAGING OUTFLOW WINDS TO 60 MPH AND POSSIBLY A FEW
TORNADOES.

THE FIRST WAVE OF THUNDERSTORMS DEVELOPING OVER THE FRONT RANGE AND
ALONG A BOUNDARY COMING OFF THE PALMER DIVIDE WILL MOVE ACROSS THE
I-25 URBAN CORRIDOR BETWEEN 2 AND 4 PM.  A FEW OF THESE STORMS WILL
BE CAPABLE OF WIND GUSTS TO 40 MPH...BRIEF HEAVY RAINFALL AND SMALL
HAIL. A STORM OR TWO MAY EVEN BECOME SEVERE NORTH OF THE DENVER
METRO AREA WITH DAMAGING HAIL...STRONG WIND AND FUNNELS CLOUDS THE
MAIN THREATS. AS THESE STORMS MIGRATE NORTHEAST INTO MORE MOIST AND
UNSTABLE AIR...ANTICIPATE RAPID DEVELOPMENT. THUNDERSTORMS...SOME OF
THEM SEVERE... ON THE FAR NORTHEAST PLAINS OF COLORADO ARE EXPECTED
COULD LINGER FOR MOST OF THE NIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

CHANCES FOR THUNDERSTORMS WILL INCREASE AGAIN THURSDAY PRIOR TO A
COLD FRONT MOVING THROUGH IN THE LATE AFTERNOON. WARMER AND DRIER
CONDITIONS WILL THEN RETURN FOR FRIDAY. A SURGE OF MOISTURE SATURDAY
AND ANOTHER WEATHER DISTURBANCE WILL INCREASE SHOWER AND
THUNDERSTORM ACTIVITY AGAIN. SUNDAY THROUGH TUESDAY WILL RETURN TO
WARMER AND DRIER CONDITIONS HOWEVER THE THREAT OF ISOLATED
THUNDERSTORMS WILL REMAIN.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE REQUESTED AFTER 2 PM TODAY. TORNADO WATCH
WILL BE ISSUED SHORTLY.

BAKER/GIMMESTAD