MESOSCALE PRECIPITATION DISCUSSION 0430
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
936 PM EDT FRI AUG 07 2015
 
AREAS AFFECTED...NORTHEASTERN CO/SOUTHERN NE/NORTHERN KS... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 080135Z - 080535Z
 
SUMMARY...AN AREA OF STRONG CONVECTION HAS CONTINUED TO PRODUCE
VERY HEAVY RAINFALL ACROSS NORTHERN CO UP INTO SOUTHWESTERN NE.
THE SOUTHERN EXTENT OF THE THUNDERSTORM COMPLEX HAS BEGUN TO TAKE
ON A WEST-EAST ORIENTATION WHICH GENERALLY ALIGNS WITH THE MEAN
STEERING FLOW. EXPECT A THREAT FOR FLASH FLOODING ALONG THIS
WEST-EAST AXIS BEFORE THE SYSTEM BECOMES MORE PROGRESSIVE IN
NATURE.

DISCUSSION...A WEAK PERTURBATION IN THE MID-LEVEL FLOW HAS HELPED
SPARK A BROAD AXIS OF STRONG TO SEVERE THUNDERSTORMS ACROSS
NORTHEASTERN CO INTO AREAS OF SOUTHWESTERN NE. SOME OF THE CLOUD
TOPS WITH THESE STRONG UPDRAFTS HAVE REACHED -75C PER RECENT IR
SATELLITE IMAGERY. WHILE THE NORTHERN EXTENT OF THE CONVECTION HAS
BECOME MORE PROGRESSIVE IN NATURE...THE SOUTHERN END ALONG THE
CO/NE/KS BORDER REGION HAS BEEN SLOWER MOVING. MULTIPLE OUTFLOW
BOUNDARIES HAVE BEEN THE SITE OF RENEWED CONVECTION WHICH HAS
ALLOWED THE ACTIVITY TO HANG UP ACROSS AREAS OF NORTHEASTERN CO.
THERE MAY BE A BRIEF PERIOD OF TRAINING IN A WEST-EAST FASHION
WHICH GENERALLY ALIGNS WITH THE PREDOMINANT MEAN STEERING FLOW.
ADDITIONALLY...THERE APPEARS TO BE NO SHORTAGE OF STORM INFLOW AS
RECENT VAD-WIND PROFILER DATA SHOWS 20 TO 30 KNOTS OF SOUTH TO
SOUTHEASTERLY FLOW AT 925 TO 850 MB. THIS SHOULD HELP SUSTAIN THE
ACTIVITY WHILE A GRADUAL PROGRESSION TOWARD THE EAST IS EXPECTED
DURING THE OVERNIGHT HOURS. THE PRIMARY CONCERN AREAS ARE OVER THE
REGIONS OF LOWER FFG VALUES WHERE HOURLY NUMBERS ARE IN THE 1 TO
1.50 INCH RANGE.

A VAST MAJORITY OF THE 12Z CAMS SHOW A HEAVY RAINFALL AXIS
STRETCHING ALONG THE CO/NE/KS BORDER REGION...GENERALLY ALIGNING
WEST TO EAST. MOST RECENTLY...THE 00Z HRRR FAVORS A FEW HOUR
PERIOD OF STRONG CONVECTION OVER THE REGIONS OF LOWER FFG WITH
LOCAL RATES POTENTIALLY NEARING AND/OR EXCEEDING THESE VALUES.
FLASH FLOODING WILL REMAIN POSSIBLE THROUGH ROUGHLY 05Z. WILL
ALLOW NIGHT SHIFT TO REASSESS THE SITUATION AS NEWER
GUIDANCE/OBSERVATIONAL DATA ARRIVES.


RUBIN-OSTER

ATTN...WFO...BOU...GID...GLD...LBF...

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

LAT...LON   41150042 40989905 40389835 39539834 39239933 
            39220226 39120385 39870434 40480324 41030223