WPC Met Watch |
|
Mesoscale Precipitation Discussion: #0436 (2018) |
(Issued at 912 AM EDT THU JUL 12 2018
) |
|
MPD Selection |
|
|
|
MESOSCALE PRECIPITATION DISCUSSION 0436
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
912 AM EDT THU JUL 12 2018
AREAS AFFECTED...CENTRAL MINNESOTA TO NORTHWEST WISCONSIN
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 121312Z - 121630Z
SUMMARY...AS ONE AREA OF THUNDERSTORMS MOVES OUT OF MINNESOTA AND
INTO WISCONSIN...ADDITIONAL SHOWERS AND THUNDERSTORMS WERE
DEVELOPING ALONG AND AHEAD OF SURFACE LOW PRESSURE MOVING OUT OF
SOUTH DAKOTA. WHILE HEAVY RAINFALL RATES ARE POSSIBLE FROM THESE
CELLS...THE CHANCES FOR FLASH FLOODING WILL BE BEST IN AREAS OF
EASTERN MINNESOTA WHICH WERE SOAKED OVERNIGHT.
DISCUSSION...RADAR SHOWED SHOWERS AND THUNDERSTORMS DEVELOPING
OVER PORTIONS OF CENTRAL MINNESOTA EARLY THIS MORNING IN VICINITY
OF A COLD FRONT MOVING ACROSS THE STATE. CELL MOTION WAS SUCH
THAT TRAINING MAY OCCUR OVER THE WESTERN/CENTRAL PART OF THE
STATE. THIS MAY ALLOW FOR RAINFALL AMOUNTS TO APPROACH FLASH
FLOOD GUIDANCE...WHICH WHICH WAS ON THE ORDER OF 1.5 TO 2 INCHES
PER 3 HOURS.
BETWEEN ONGONG RAINFALL LINGERING FROM OVERNIGHT CONVECTION AND
THE POTENTIAL FOR THIS NEW CONVECTION OVER MINNESOTA TO BRING
ADDITIONAL RAINFALL TO AREAS SOAKED OVERNIGHT...THINKING IS THAT
THIS AREA WILL BE MORE AT RISK FOR ADDITIONAL FLASH FLOODING OR
WORSENING OF ONGOING FLOODING. RAINFALL AMOUNTS FROM OVERNIGHT
INCLUDED AT LEAST ONE 5 INCH AMOUNT ON THE SOUTH SIDE OF LAKE
MILLE LACS...AND DUAL POL RADAR ESTIMATES OF 2 TO 5 INCH AMOUNTS
EXTENDING EASTWARD FROM THERE TOWARDS THE MN/WI STATE LINE. AS A
RESULT...FLASH FLOOD GUIDANCE VALUES WILL BE CONSIDERABLY LOWER IN
THIS REGION.
GENERALLY... CONVECTION WILL MORE FOCUSED ON THE EDGE OF THE CAP
(ROUGHLY OUTLINED BY THE +12C ISOTHERM AT 700MB). H85 FLOW ON THE
ORDER OF 30 KTS WILL COTINUE TO FEED DEEP MOISTURE INTO THE
CONVECTION. WITH THE LINE-PARALLEL FLOW AND FAVORING NEW UPDRAFT
FORMATION JUST WSW-W OF A W-E ORIENTED LINE INTO MID MORNING
BANN
ATTN...WFO...ABR...DLH...FGF...MPX...
ATTN...RFC...NCRFC...
LAT...LON 46179280 45879182 45449156 45349319 45349421
45079610 45789645 45909540 46119386
Last Updated: 912 AM EDT THU JUL 12 2018
|