Severe Thunderstorm Warning 92, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
300 PM MDT MON JUL 9 2001

UPPER RIDGE NEARLY STATIC WITH ANALYSIS SHOWING CENTER OVR OK
PANHANDLE.  PRECIP H20 PLOT HAS HIGHEST PERCENTAGE OF NORMAL VALUES
OVR GREAT BASIN WHERE UPPER FLOW IS IN DIRECT CONNECTION WITH DAILY
CONVECTION OVER MEXICAN MTNS.  FOR THE BOU CWA...PLENTY OF RESIDUAL
SFC MOISTURE TO WORK WITH TODAY AS DEW POINTS ARE GENERALLY IN THE
MID 50S TO LOWER 60S.  SOME OF THE HEAVY RAIN AREAS OF THE LAST TWO
DAYS IN AND NEAR THE URBAN CORRIDOR SHD AGAIN BE THE FOCUS FOR
TSTORMS AND HEAVY RAINS AGAIN THIS EVE AND TUE.  CURRENT AND FCST
SOUNDINGS HAVE STORM MOTION IN THE SLOW 5 TO 11 KT RANGE.  FOR
TONIGHT...MESO-ETA INDICATES A NORTHERLY SURGE TO ENTER THE CWA NEAR
00Z-03Z FROM AFTERNOON CONVECTION IN WYO AND LAST NIGHTS MCS IN
NEB.  HAVE NOTICED EASTERLY WINDS IN THE MODELS EVERY AFT AND THIS
MAY BE MORE DUE TO THE MODELS RESPONSE TO DIFFERENTIAL DAYTIME
HEATING AND SFC WIND REGIMES RATHER THAN ACTUAL COOL FRONTS.  WILL
WATCH HOW THIS SURGE ENTERS AREA FOR TONIGHT AS WINDS ARE NEARLY
CALM AND CHAOTIC IN WYO THIS MORNING...BUT THERE ARE STRONG MOISTURE
RICH EASTERLIES IN SOUTHERN NEB REACHING NE PLAINS ATTM.  AT ANY
RATE...CONVECTION A VERY GOOD BET FOR CWA TONIGHT AS THESE STRONG
EASTERLIES SHD HELP TO SUSTAIN UPSLOPE/WARM RAIN PROCESSES THROUGH
LATE EVE.  MESO-ETA CONFIRMS THIS BY GIVING WIDESPREAD HEAVY PRECIP
VALUES IN THE 1.00 TO 1.50 INCH NEIGHBORHOOD ALONG THE URBAN
CORRIDOR AND FOOTHILLS.  UPSLOPE IS ALSO EXPECTED TO DEEPEN FROM SFC
TO THE 700-650MB LVL BY 03Z WITH 2-3DEGC COOLING AT 700MB.  HENCE...
A FLASH FLOOD WATCH WILL BE APPROPRIATE FOR TONIGHT AND WILL ALSO
KEEP THE HEAVY RAIN WORDING IN TONIGHT.  IF HEALTHY RAIN DOES COMES
TO THE AREA TONIGHT...EVEN MORE RESIDUAL MOISTURE IS AVAIL FOR
TOMORROW WITH FCST SOUNDINGS EVEN CLOSER TO MOIST ADIABATIC.  WEAK
CYCLONIC CURVATURE CURRENTLY DEVELOPING OVER NORTHERN MEX/EL PASO TX
VICINITY AND IT WILL BE INTERESTING TO SEE IF THAT PLAYS A ROLE IN
TUESDAYS WEATHER WITH RESPECT TO ITS TIMING OF DAYTIME HEATING OR
WEATHER IT PRODUCES A DRY SLOT.  OTHERWISE...DYNAMICS ARE RATHER
BENIGN IN THE RIDGE...BUT WILL KEEP THE SCT POPS GOING INTO WED AS
WELL.  AVN AND ETA HAVE RIDGE HOLDING STEADY WITH THE DAILY SFC
EASTERLIES AND 850-700MB RHS STAYING RICH OVER DISTRICT.  WILL LOOK
FOR HIGHER TERRAIN TO ONCE AGAIN TO BE FOCUS FOR INITIATION.  HIGH
DEW PTS HAVE BEEN A GOOD GUIDE FOR NIGHTTIME LOWS.  WOULD LIKE TO
CONSIDER FOG AND LOW CLOUDS FOR THE EACH EVE PD WITH HIGH MOISTURE
AND OVERNIGHT CLEARING...BUT WILL HOLD OF FOR EVE SHIFTS.  LOOKS
LIKE THE STREAK OF 90S OR HIGHER IS IN JEOPARDY.  IF TDY FAILS...THE
STREAK ENDS AT 11 WHICH HAS HAPPENED ONLY 3 OTHER SUMMER IN DENVER
HISTORY.

EXTENDED PD THURS THRU MON...RIDGE REMAINS IN THE SAME VICINITY THRU
PD...HOWEVER THE CENTER RETROGRADES WEST ABOUT 500 MILES AND PARKS
ITSELF OVR NEW MEX BY SUN WITH DESERT HEAT KEEPING IT ALIVE.  THIS
WOULD TEND TO SHUT OFF THE TROPICAL MID AND UPPER LVL MOISTURE FROM
MEXICO.  WILL NOT PINPOINT WHEN DRYEST DAY ARRIVES...ESPECIALLY WITH
NEAR SATURATED SOILS IN CWA...SO A CHANCE EACH DAY WILL WORK.  FSCT
TEMPS TREND SLIGHTLY COOLER TO NEAR NORMAL JULY VAULES THROUGH PD.

FREDIN

.DEN...FLASH FLOOD WATCH UNTIL MIDNIGHT...ZNS...35>36..38>43..45.

COZ030>051-092200-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
140 PM MDT MON JUL 9 2001

...UPDATED FOR FLASH FLOOD WATCH...

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

...FLASH FLOOD WATCH EASTERN FOOTHILLS AND URBAN CORRIDOR UNTIL
   MIDNIGHT TONIGHT...

SYNOPSIS...TROPICAL MONSOONAL MOISTURE AT MID AND HIGH LEVELS
WILL CONTINUE TO CIRCULATE AROUND AN UPPER LEVEL RIDGE OF HIGH
PRESSURE ANCHORED OVER THE CENTRAL GREAT PLAINS AND ENTRAIN MOISTURE
OVER THE CENTRAL ROCKY MOUNTAINS.  WHILE THE CURRENT SATELLITE LOOP
SUGGESTS AN INTRUSION OF DRIER AIR ALOFT FROM THE SOUTHEAST OVER THE
AREA THIS MORNING...FORECAST MODEL DATA INDICATE GREATER RAINFALL
AND HIGHER AMOUNTS OF MOISTURE OVER THE AREA LATE THIS AFTERNOON
INTO THE EVENING.  A WEAK UPPER LEVEL DISTURBANCE IN SOUTH TO
SOUTHWESTERLY FLOW ALOFT WILL CONTRIBUTE TO THE OVERALL INSTABILITY
OF THE AIR MASS AS WILL THE LOW LEVEL MOISTURE OVER THE HIGH PLAINS
WHERE SURFACE DEWPOINTS WILL REMAIN IN THE UPPER 50S AND LOWER 60S.
INCREASING DEEP LOW LEVEL EASTERLY UPSLOPE FLOW LATE THIS AFTERNOON
AND EVENING OVER THE HIGH PLAINS WILL ENHANCE THUNDERSTORM
DEVELOPMENT IN AND NEAR THE EASTERN FOOTHILLS.  ADEQUATE DIRECTIONAL
SHEAR WILL BE PRESENT FOR THE DEVELOPMENT OF ISOLATED SEVERE
THUNDERSTORMS OVER THE PLAINS EVEN THOUGH THE OCCURRENCE OF LARGE
HAIL MAY BE REDUCED BY FREEZING LEVELS WELL ABOVE 16 THOUSAND FEET
MSL.  AMPLE MOISTURE WILL BE PRESENT FOR HEAVY THUNDERSTORM RAINS.
TRAINING OF STORMS WILL CONTRIBUTE TO INCREASED TOTAL RAINFALL.

SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM OVER THE MOUNTAINS
AND EASTERN FOOTHILLS DURING THE EARLY AFTERNOON AND MOVE TO THE
NORTH AND NORTHEAST OVER THE URBAN CORRIDOR AND HIGH PLAINS DURING
THE LATE AFTERNOON AND EVENING.  ISOLATED SEVERE THUNDERSTORMS WILL
PRODUCE LARGE HAIL...DAMAGING WINDS AND HEAVY RAIN WITH RAINFALL OF
3.00 TO 3.50 INCHES POSSIBLE IN AN HOUR.  THIS AMOUNT OF RAINFALL
WILL CAUSE URBAN AND SMALL STREAM FLOODING.  THERE IS ALSO A
POTENTIAL FOR MAJOR STREAM AND RIVER FLOODING LATE THIS AFTERNOON
AND EVENING ESPECIALLY FOR AREAS IN AND NEAR THE EASTERN FOOTHILLS
AND URBAN CORRIDOR WHERE THE SOIL IS ALREADY SATURATED FROM HEAVY
RAINS OF THE LAST FEW DAYS.

REAL TIME RAINFALL REPORTS WILL BE NEEDED.

GARD...WFO BO$ULDER