MESOSCALE PRECIPITATION DISCUSSION 0246
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
516 AM EDT FRI SEP 13 2013
 
AREAS AFFECTED...ERN CO...NW KS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 130915Z - 131415Z
 
SUMMARY...WHILE HISTORIC FLOODING WAS STILL ONGOING...THE THREAT
OF ADDITIONAL HEAVY RAINFALL WILL BE AT A MINIMUM THROUGH THE REST
OF THE EARLY MORNING HOURS. THE GREATEST CHANCE FOR HEAVY RAIN
WILL BE ALONG THE PALMER DIVIDE.

DISCUSSION...LOOPING THE REGIONAL RADAR MOSAIC AND CONSIDERING
LATEST MESOSCALE GUIDANCE IT WOULD APPEAR THAT A REGION OF
ENHANCED WARM ADVECTION WAS MIGRATING NORTHWARD THROUGH CO AND FAR
WRN KS. SINCE 06Z...RAIN HAD BEEN HEAVIEST WHERE THIS WARM
ADVECTION COINCIDED WITH AN AXIS OF WEAK INSTABILITY OVER THE
EASTERN PLAINS OF COLORADO TO THE SOUTH OF INTERSTATE 70. DEEPER
CONVECTIVE CELLS WERE PARTICULARLY FOCUSED IN LINCOLN
COUNTY...LIKELY OWING TO ADDITIONAL ENHANCEMENT OF THE LOW LEVEL
UPSLOPE FLOW BY THE SOUTH-FACING SLOPE OF THE PALMER DIVIDE.

AT THE SAME TIME...RAIN RATES HAD DWINDLED WITHIN THE NOW
STRATIFORM PRECIPITATION ARCHING FROM NW KS TO NRN CO...AND WITHIN
THE SHOWERY PRECIPITATION ALONG THE ROCKIES FRONT RANGE. AT
09Z...RECENT RADAR ESTIMATES WERE OF A FEW TENTHS OF AN INCH PER
HOUR IN MOST OF THE ACTIVITY...WITH PERHAPS A HALF INCH PER HOUR
IN THE HEAVIER CELLS ALONG THE PALMER DIVIDE.

WHILE THE AXIS OF WARM ADVECTION AND ASSOCIATED ASCENT WILL
CONTINUE TO LIFT TOWARD FAR NE CO... THE INSTABILITY AXIS WILL BE
LEFT BEHIND...WITH THE HRRR PREDICTING NO MORE THAN 250 J/KG
NEAR-SFC BASED CAPE NORTH OF I-70 BY 15Z. IT APPEARS UNLIKELY IN
THIS SCENARIO THAT HEAVY RAIN WOULD DEVELOP AS FAR NORTH AS THE
CO/NE/WY BORDERS...AS WAS SUGGESTED BY EARLIER HI-RES GUIDANCE.
THE 00Z GUIDANCE SUITE DID SHIFT SOUTHWARD...AND IT APPEARS THE
ONLY PLACE LEFT WITH ANY APPRECIABLE BOUYANCY WILL BE EAST-CENTRAL
CO THROUGH 15Z. 05Z HRRR REFLECTIVITY/QPF SUPPORTS THIS NOTION.

THUNDERSTORMS WITH HEAVY RAIN WILL CERTAINLY BE POSSIBLE LATER
TODAY OVER A BROADER AREA. EVENTS THIS
AFTERNOON...HOWEVER...SHOULD BE MORE TYPICAL...WITH INCREASED
WESTERLY COMPONENT TO MID LEVEL FLOW YIELDING DEEPER...MORE
CLASSIC LOOKING UPDRAFTS WITH MOTIONS TOWARD THE E AND NE...AND
LESS CHANCE OF LONG DURATION TRAINING.

BURKE

ATTN...WFO...GLD...PUB...BOU...

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

LAT...LON   38200273 38940158 39720208 40330332 40360437 39600517
            38840523 38290446 38200273