000
FXUS65 KBOU 282144
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
344 PM MDT MON JUL 28 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 343 PM MDT MON JUL 28 2014

UPPER LEVEL RIDGE WILL BE SUPPRESSED INTO SOUTHERN NEW MEXICO AND
INTO MEXICO TONIGHT AND TUESDAY AS SHORT WAVES ROUND THE RIDGE.
MONSOONAL MOISTURE WILL ROTATE AROUND THE RIDGE AND CONTINUE TO
STREAM OVER THE STATE. PRECIPITABLE WATER VALUES ARE AROUND ONE INCH
ALONG THE FRONT RANGE. SCATTERED CONVECTION WILL CONTINUE INTO
THE EARLY EVENING OVER THE HIGHER TERRAIN WITH HEAVY RAIN BEING
THE BIGGEST THREAT. APPEARS THE LOWER ELEVATIONS ARE SOME WHAT
CAPPED SO WILL LOWER POPS TO ISOLATED. CAN`T RULE OUT AN ISOLATED
SEVERE WIND GUST THIS AFTERNOON AND EARLY EVENING...THOUGH THE
TREAT IS LOW.

WITH THE LACK OF UPPER LEVEL SUPPORT...STORMS WILL END LATE THIS
EVENING AS THE AIRMASS STABILIZES. COULD SEE LOW CLOUDS TOWARDS DAY
BREAK DUE TO THE MOIST AIRMASS...BUT SOME DRY AIR COULD PREVENT
THIS.

THE FIRST OF TWO SHORT WAVES WILL MOVE INTO COLORADO TUESDAY AND
PROVIDE LARGE SCALE LIFT ACROSS NORTHEAST COLORADO. ISOLATED STORMS
MAY FORM LATE TUESDAY MORNING. DURING THE AFTERNOON SCATTERED TO
NUMEROUS STORMS ARE EXPECTED TO DEVELOP. MOISTURE WILL INCREASE
THROUGH THE DAY. BY LATE AFTERNOON...PRECIPITABLE WATER VALUES WILL
REACH AN INCH IN THE FOOTHILLS... 1.25 ACROSS THE URBAN CORRIDOR AND
CLOSE TO 1.5 INCHES ON THE PLAINS. CAPES WILL REACH 500 TO 1000
J/KG...THIS COMBINED WITH SOME DIRECTION SHEAR IN THE ATMOSPHERE
COULD LEAD TO A COUPLE MARGINAL SEVERE STORMS...WITH STRONG WINDS
POSSIBLE. HOWEVER...MAIN CONCERN WITH THE STORMS WILL BE HEAVY
RAIN WHERE ONE INCH OF RAINFALL COULD FALL IN AS LITTLE AS 15-20
MINUTES FROM THE STRONGEST STORMS. THREAT FOR FLASH FLOODING WILL
BE HIGH AND CONTINUE INTO TUESDAY NIGHT AND WEDNESDAY. A FLASH
FLOOD WATCH HAS BEEN ISSUED FOR MUCH OF NORTHEAST COLORADO FOR
TUESDAY AFTERNOON AND MOST OF WEDNESDAY. FOR ADDITIONAL DETAILS
ABOUT THE HEAVY RAIN THREAT...SEE THE HYDROLOGY SECTION BELOW.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 343 PM MDT MON JUL 28 2014

SHOWERS AND THUNDERSTORMS TO CONTINUE TUESDAY NIGHT...WITH PERHAPS
SOME DECREASE IN THE ACTIVITY OVERNIGHT AS SUBSIDENCE MOVES
OVERHEAD. STEERING WINDS TO BE WEAK...SO SLOW MOVING STORMS
EXPECTED. WITH MOIST AIRMASS IN PLACE...THREAT FOR LOCALLY HEAVY
RAIN EXISTS ALONG WITH A FLASH FLOOD POTENTIAL. ON WEDNESDAY...
NORTHWEST FLOW ALOFT CONTINUES WITH GOOD UPSLOPE UP TO ABOUT 650
MB. SHOWERS AND THUNDERSTORMS SHOULD BE ONGOING DURING THE
MORNING...THOUGH THERE MAY BE A SLIGHT DECREASE WITH MID LEVEL
SUBSIDENCE. BY AFTERNOON...NEXT MID LEVEL SHORTWAVE WHICH MODELS
SHOW OVER NORTHWEST COLORADO AT 12Z IS EXPECTED TO MOVE ACROSS THE
AREA WITH INCREASING LIFT. THIS SHOULD HELP ENHANCE THE ACTIVITY.
STEERING WINDS FAIRLY LIGHT...SO STORMS TO CONTINUE TO BE SLOW
MOVING. HEAVY RAIN THREAT WITH THE POTENTIAL FOR FLASH FLOODING TO
CONTINUE THROUGH THE AFTERNOON. THUNDERSTORM ACTIVITY TO DECREASE
DURING THE EVENING AS SLIGHTLY DRIER AND SUBSIDENT AIR MOVES IN
FROM THE NORTH. STILL SOME THREAT FOR LOCALLY HEAVY RAIN...THOUGH
FLOOD THREAT SHOULD BE DECREASING.

BY THURSDAY...FLOW ALOFT BECOMES NORTH NORTHWEST AS SHORTWAVE MOVES
SOUTHEAST OF COLORADO. AIRMASS SLIGHTLY DRIER WITH PRECIPITABLE
WATER VALUES AROUND AN INCH ACROSS THE PLAINS AND BETWEEN 0.60 AND
0.70 INCHES OVER THE MOUNTAINS. AFTER SOME MORNING LOW LOW CLOUDS
AND PERHAPS FOG...THUNDERSTORMS WILL AGAIN BE POSSIBLE WITH THE
BEST CHANCE OVER THE HIGHER TERRAIN. BRIEF HEAVY RAIN WILL BE
POSSIBLE THOUGH THREAT FOR FLOODING LOOKS LOW. SOME MODERATION IN
TEMPERATURES WITH HIGHS IN THE MID AND UPPER 70S ACROSS THE
PLAINS.

ON FRIDAY...THE NORTH NORTHWEST FLOW ALOFT TO CONTINUE WITH A
SLIGHTLY DRIER AIRMASS. STILL SUFFICIENT MOISTURE FOR A CHANCE OF
THUNDERSTORMS...MAINLY ACROSS THE MOUNTAINS. MODELS HINT AT A MID
LEVEL SHORTWAVE MOVING ACROSS THE AREA DURING THE AFTERNOON WHICH
COULD INCREASE THE CHANCES FOR THUNDERSTORMS. HIGHS TO BE A BIT
WARMER...WITH READINGS AROUND 80 DEGREES OVER THE PLAINS.

FOR THE LATER DAYS...SATURDAY THROUGH MONDAY. NORTHWEST FLOW
ALOFT TO PREVAIL THROUGH THE PERIOD. ENOUGH MOISTURE FOR A CHANCE
OF AFTERNOON AND EVENING THUNDERSTORMS OVER THE MOUNTAINS AND A
SLIGHT CHANCE ACROSS THE PLAINS EACH DAY. BOTH GFS AND ECMWF SHOW
SOME INCREASE IN MOISTURE LATE SUNDAY INTO MONDAY WITH HINTS OF A
MID LEVEL SHORTWAVE WHICH COULD LEAD TO AN INCREASING CHANCE OF
THUNDERSTORMS BY MONDAY. TEMPERATURES TO REMAIN BELOW NORMAL.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z TUESDAY LATE AFTERNOON)
ISSUED AT 343 PM MDT MON JUL 28 2014

SCATTERED TO ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS THE DENVER
AREA THROUGH ABOUT 03Z. MAIN THREAT WILL BE HEAVY RAIN AND GUSTY
OUTFLOW WINDS TO 40 KNOTS. WIND DIRECTION MAY CHANGE A TIME OR TWO
DUE TO OUTFLOWS FROM NEARBY THUNDERSTORMS. THERE WILL BE A CHANCE
FOR LOW CLOUDS TUESDAY MORNING...THOUGH DRY AIR COULD PREVENT THIS
FROM HAPPENING. THUNDERSTORMS WILL LIKELY AFFECT THE DENVER AIRPORTS
TUESDAY AFTERNOON...AFTER 19Z. HEAVY RAIN AND OUTFLOW WIND GUSTS TO
40 KNOTS WILL BE POSSIBLE.

&&

.HYDROLOGY...
ISSUED AT 343 PM MDT MON JUL 28 2014

AIRMASS IS MOIST TODAY AND STORMS HAVE BEEN SLOW MOVING WHICH IS
LEADING TO A SLIGHT CHANCE OF FLASH FLOODING. FLOOD PRONE AREAS ARE
THE AREAS OF CONCERN TODAY. ONLY ISOLATED TO SCATTERED STORMS ARE
EXPECTED...SO THE OVERALL THREAT WILL BE LOW.

THE THREAT FOR FLASH FLOODING WILL BE MUCH HIGHER TUESDAY AFTERNOON
AND THROUGH WEDNESDAY. MOST OF THE BOXES HAVE BEEN CHECKED FOR
HEAVY RAIN AND FLOODING TUESDAY AFTERNOON INTO WEDNESDAY. THEY
INCLUDE...A VERY MOIST AIRMASS WITH PRECIPITABLE WATER VALUES NEAR
THE 99TH PERCENTILE...DEEP WARM CLOUD LAYER OF 8000-9000 FEET...DEEP
SKINNY CAPE WITH VALUES LESS THAN 1000 J/KG...AN EASTERLY WIND FLOW
UP TO 650 MB WHICH WILL PRODUCE AN UPSLOPE FLOW AND HELP STORMS
REGENERATE/TRAIN OVER THE SAME AREA. A FLASH FLOOD WATCH IS IN
EFFECT FOR MOST OF NORTHEAST COLORADO TUESDAY AFTERNOON THROUGH MOST
OF WEDNESDAY.

GRADUAL DRYING STILL EXPECTED THURSDAY INTO THE WEEKEND WITH LESS
THUNDERSTORM ACTIVITY. HOWEVER...THERE WILL STILL BE SOME THREAT
FOR HEAVY RAINFALL THOUGH THE FLOOD RISK SHOULD BE LOWER.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR COZ033>047-049.

&&

$$

SHORT TERM...MEIER
LONG TERM...D-L
AVIATION...MEIER
HYDROLOGY...D-L/MEIER

NWS BOU Office Area Forecast Discussion