Flash Flood Warning 6, NWS Denver/Boulder, CO

000 
WGUS75 KBOU 122130
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
327 PM MDT TUE JUN 12 2007

COC095-122215-
PHILLIPS CO-
327 PM MDT TUE JUN 12 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM MDT FOR
EASTERN PHILLIPS COUNTY...

AT 327 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
LIGHT TO MODERATE RAIN CONTINUING OVER EASTERN PHILLIPS COUNTY.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
PLEASANT VALLEY AND AMHERST.

DOPPLER RADAR ESTIMATES THAT UP TO 3 INCHES OF RAIN FELL EARLIER 
THIS AFTERNOON FROM NEAR AMHERST TO SOUTH OF PLEASANT VALLEY.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING ON 
WILDHORSE AND FRENCHMAN CREEKS AND ALONG HIGHWAYS 6 AND 23.  IN 
ADDITION FLASH FLOODING MAY OCCUR ON COUNTRY ROADS AND NORMALLY DRY 
WASHES AND ARROYOS.

LAT...LON 4046 10227 4045 10206 4074 10206 4073 10222

$$

RPK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
1145 AM MDT TUE JUN 12 2007

.UPDATE...HAVE ALREADY ISSUED FLASH FLOOD WATCH FOR ZNS 48..50>51
THRU TNT. SATURATED SOILS FROM LAST NIGHTS STORMS AND ON-GOING
STORMS WILL RESULT IN FLASH FLOODING THRU TNT. TORNADO WATCH ALSO
OUT FOR ZONES 50 AND 51 THRU 00Z WITH DIRECTIONAL SHEAR AT LOW LVLS.
MORE LATER...

.SHORT TERM...MID LEVEL LOW CLOSING OFF NEAR FOUR CORNERS. I DID NOT
REALLY LIKE THE DETAILS OF THE 00Z MODEL RUNS WITH THE TIMING OF THE
LOW...POSITION OF THE BAND OF FORCING WRAPPING AROUND THE NORTH
SIDE...AND ESPECIALLY THE LOW LEVEL FEATURES. 06Z NAM SEEMS TO DO A
BETTER JOB OF ALL OF THE ABOVE. OF PARTICULAR NOTE IS THE EXTENT TO
WHICH MILD AND MOIST AIR IS WRAPPING BACK INTO NORTHEASTERN
COLORADO. THE PLAN WAS TO HAVE POTENTIALLY COOLER AIR SPILLING IN
BEHIND THE LOW AS IT MOVED EAST. INSTEAD WE HAVE A WEAK SURFACE
TROUGH PIVOTING IN A WAY THAT KEEPS THE EASTERLY WINDS ACROSS MOST
OF OUR AREA...SO INCREASED INSTABILITY INSTEAD OF LESS. THE COOLER
AIR IS UP IN WYOMING...BUT WILL ARRIVE LATER. THIS INCREASES THE
THREAT OF STRONG CONVECTION TODAY. CLOUD COVER AND THE LIKELY EXTENT
OF THE CONVECTION WILL LIMIT THE STRENGTH OF CELLS HOWEVER...SO I
WILL NOT GET CARRIED AWAY. EAST OF FORT MORGAN AND LIMON WHERE DEW
POINTS WILL BE PUSHING 60 DEGREES CAPES COULD BE IN THE 1000-2000
J/KG RANGE...BUT AGAIN OTHER ENVIRONMENTAL FACTORS WILL LIMIT THE
THREAT OF SEVERE HAIL OR WIND. MOST LIKELY PROBLEM WILL BE HEAVY
RAINFALL. CELL MOTION LOOKS TO BE AT LEAST 10 MPH MOST OF THE
DAY...BUT WE COULD HAVE PROBLEMS FROM TRAINING OR OUTFLOW
PROPAGATION OFFSETTING THE CELL MOTION. MOST LIKELY AREA FOR THIS
WOULD BE NORTH OF THE LOW AND ALONG WHATEVER SURFACE BOUNDARY WE
EVENTUALLY WIND UP WITH. ALSO GREATER MOISTURE CONTENT ROUGHLY NORTH
AND EAST OF LIMON. THOUGHT ABOUT A FLASH FLOOD WATCH FOR THE
NORTHEAST CORNER BUT DECIDED TO LET THE MORNING CREW DO A BIT MORE
ANALYSIS...THEY MAY HAVE A BETTER IDEA HOW THINGS WILL COME
TOGETHER. I WILL RAISE POPS AND MENTION HEAVY RAIN ON THE PLAINS...
AS COMBINATION OF LIFT/MOISTURE/INSTABILITY APPEARS TO BE UNIVERSAL.
SLOWED EASTWARD PROGRESSION OF EVERYTHING OVERNIGHT AS WELL...AND
TENDED TO GO WITH MORE SHOWERS VERSUS STORMS BEHIND THE LOW.

.LONG TERM...FOR WEDNESDAY...UPPER LOW WILL LINGER OVER ERN CO WITH
A DRIER NWLY FLOW DEVELOPING IN THE AFTN AND EVENING.  LOOKS LIKE
BEST CHC OF PCPN WILL BE ALG THE ERN BORDER IN THE MRNG.  ENUF
CAPE GENERATED FM THE WRF IN THE AFTN TO KEEP SLGT CHC TSTMS GOING
IN THE AFTN AND EVENING.  CAPES GENERALLY RANGE FM 400-700 J/KG
ALONG THE URBAN CORRIDOR WEDNESDAY AFTN...MORE STABLE TO THE EAST.
AN UPPER LEVEL RIDGE WILL MOVE INTO THE CWFA WEDNESDAY NIGHT INTO
THURSDAY.  QG VERTICAL VELOCITIES ON THURSDAY ARE NEARLY NEUTRAL AOA
700 MB. THE GFS SHOWS LITTLE IN THE WAY OF QPF OVER NERN CO THURSDAY
AFTN AND EVENING...WHILE THE WRF IS MORE GENEROUS...ESPECIALLY IN
THE MTNS AND ALG THE URBAN CORRIDOR. FOR NOW WILL JUST INTRODUCE
SOME ISOLD POPS IN THE MTNS.  WL LEAVE THE RMNDR OF THE FCST GRIDS
AS THEY WERE.  AN UPPER LEVEL RIDGE WILL BE OVER THE DESERT
SOUTHWEST WITH A WEAK NNELY FLOW OVER THE CWFA.  MAIN FOCUS FOR DEEP
CONVECTION SHOULD BE ALONG THE HIR TERRAIN AND THIS ALREADY
REFLECTED IN THE GRIDS.  THE RIDGE WILL CONTINUE TO BE THE MAIN
SYNOPTIC INFLUENCE OVER THE WEST THROUGH THE WEEKEND.  THE GFS SHOWS
A SYSTEM MOVING ACRS THE NRN TIER STATES SUNDAY AFTN...WITH ITS
ASSOCIATED FRONT MOVING INTO THE REGION LATE SUNDAY NIGHT. THERE
COULD BE A BETTER CHC OF PCPN AT THAT TIME.  CURRENT SLGT CHC POPS
ON SUNDAY AFTN/EVENING WILL SUFFICE FOR NOW.

&&

.AVIATION...SHOWERS WILL GRADUALLY INCREASE IN COVERAGE THROUGH
EARLY AFTERNOON...THEN SHOWERS AND THUNDERSTORMS ARE LIKELY. WHILE
VFR CONDITIONS ARE EXPECTED TO PREVAIL...PERIODS OF MVFR CEILINGS
AND VISIBILITIES ARE EXPECTED DURING THE HEAVIER SHOWERS DURING THE
LATE AFTERNOON AND EVENING.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH UNTIL 12Z WED
FOR ZONES 48..50>51.

&&

SWE/CMG/COOPER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1050 AM MDT TUE JUN 12 2007

COZ030>051-131200-
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-
1050 AM MDT TUE JUN 12 2007

...FLASH FLOOD WATCH FOR FAR NORTHEAST COLORADO THROUGH TONIGHT...

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

.DAY ONE...TODAY AND TONIGHT

NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE TO STRENGTHEN OVER
FAR NORTHEAST COLORADO THIS AFTERNOON. THE MAIN THREAT WILL BE VERY
HEAVY RAIN AND POSSIBLE FLASH FLOODING WITH RAINFALL RATES UP TO 2
INCHES IN LESS THAN AN HOUR. THERE IS ALSO ENOUGH INSTABILITY AND
HIGH SURFACE MOISTURE TO GENERATE AN ISOLATED SEVERE STORM WITH HAIL
UP TO ONE INCH IN DIAMETER.

FURTHER WEST TOWARDS THE FRONT RANGE...SHOWERS AND THUNDERSTORMS
WILL ALSO DEVELOP DURING THE AFTERNOON HOURS. AGAIN THE MAIN THREAT
WILL BE HEAVY RAIN WITH RAINFALL RATES UP TO ONE INCH IN LESS THAN
AN HOUR. THE SEVERE THREAT IS MINIMAL SO ONLY SMALL HAIL IS EXPECTED
WITH THE STORMS.

THE STORMS WILL END LATER TONIGHT AS AN UPPER LEVEL STORM SYSTEM
MOVES INTO EASTERN COLORADO LATER TONIGHT AND BRINGS DRIER AIR
ACROSS WESTERN PORTIONS OF THE AREA.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED OVER THE FAR EASTERN PLAINS OF
COLORADO THROUGH THIS EVENING. RAINFALL AND FLOODING REPORTS WILL
ALSO BE APPRECIATED.

SWE/046