MESOSCALE PRECIPITATION DISCUSSION 0399
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 PM EDT THU JUN 30 2016
 
AREAS AFFECTED...SOUTHEAST WY...CENTRAL AND NORTHERN CO...EXTREME
WESTERN NEB 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 301957Z - 010100Z
 
SUMMARY...THUNDERSTORMS INITIATING OVER SOUTHEAST WY/NORTHERN CO
WILL EXPAND SOUTHEASTWARD THROUGH LATE-AFTERNOON WHILE GRADUALLY
BECOME MORE ORGANIZED AND EXPANSIVE IN COVERAGE.

DISCUSSION...IR SATELLITE IMAGERY SHOWS EXPANDING COLD CONVECTIVE
TOPS OVER PORTIONS OF SOUTHEAST WY...NEAR THE LARAMIE RANGE...AND
ALSO OVER FAR NORTHERN CO NEAR THE FRONT RANGE. STRONG DIURNAL
HEATING IS CURRENTLY SUPPORTING MLCAPE VALUES OF 1000 TO 1500 J/KG
IN A GENERAL NW/SE AXIS OVER SOUTHEAST WY AND OUT INTO ESPECIALLY
NORTHEAST CO. A FRONT MEANWHILE IS STALLED OUT ACROSS THIS
REGION...AND SURFACE OBSERVATIONS SHOW INCREASINGLY MOIST AND
CONFLUENT LOW LEVEL FLOW FOCUSING ALONG THE BOUNDARY. GOES-SOUNDER
PWATS HAVE BEEN SLOWLY INCREASING OVER THE LAST COUPLE OF
HOURS...WITH VALUES OF 1.1 TO 1.3 INCHES OVER THE HIGH PLAINS AS
18Z. 

THE GLOBAL MODELS TAKE A SHORTWAVE TROUGH SEEN IN WV IMAGERY OVER
NORTHERN UT GRADUALLY OFF TO THE EAST TOWARD NORTHERN CO THROUGH
THIS EVENING...HOWEVER THE GUIDANCE ALONG WITH SATELLITE TRENDS
ALSO INDICATES SOME MODEST VORT ENERGY EJECTING THROUGH NORTHERN
AND THEN NORTHEAST CO WHICH IS OUT AHEAD OF THE MAIN SHORTWAVE
TROUGH. THIS LEAD ENERGY WILL INTERACT WITH THE SURFACE FRONT AND
THE INCREASINGLY MOIST AND UNSTABLE BOUNDARY LAYER FOR MORE
ORGANIZED CONVECTION TO DEVELOP.

THE CIRA LPW PRODUCT SHOWS A FAIR AMOUNT OF MOISTURE ALREADY
FOCUSED IN THE 700MB/300MB LAYER. THIS COUPLED WITH THE BOUNDARY
LAYER MOISTURE FLUX IN VICINITY OF THE FRONT SHOULD HELP LEAD TO
EFFICIENT RAINFALL PRODUCERS WITH ENHANCED RATES. STORM
PROPAGATION SHOULD GENERALLY BE OFF TO THE SOUTHEAST THROUGH
LATE-AFTERNOON WITH CELLS TENDING TO MERGE AND BECOME MORE
ORGANIZED AS EVENING APPROACHES. HIRES GUIDANCE INCLUDING THE 12Z
WRF-ARW AND 12Z WRF-NMMB SUGGEST STORM TOTALS THROUGH 00Z OF 1 TO
2 INCHES WITH ISOLATED HEAVIER AMOUNTS...BUT THE DEGREE OF DEEPER
MOISTURE IN PLACE SUGGESTS THAT HEAVIER TOTALS WILL BE POSSIBLE
THAT MAY BE ON THE ORDER OF 3 TO 4 INCHES...AND ESPECIALLY WITH
EXPECTED RAINFALL RATES OF 1.5 INCHES/HR.

WILL CONTINUE TO MONITOR THE SET-UP BUT FLASH FLOODING WILL BE A
CONCERN AS THE CELLS CONTINUE TO ORGANIZE AND INTENSIFY.

ORRISON

ATTN...WFO...BOU...CYS...PUB...

ATTN...RFC...ABRFC...CBRFC...MBRFC...

LAT...LON   42340550 42160463 41780408 41010369 39540333 
            38860364 38630442 39200525 40300586 41360641 
            42050625