WPC Met Watch |
|
Mesoscale Precipitation Discussion: #0791 (2017) |
(Issued at 1141 AM EDT SAT SEP 09 2017
) |
|
MPD Selection |
|
|
|
MESOSCALE PRECIPITATION DISCUSSION 0791
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1141 AM EDT SAT SEP 09 2017
AREAS AFFECTED...SOUTH FLORIDA
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 091545Z - 092045Z
SUMMARY...TRAINING WITHIN OUTER BAND OF IRMA POSSIBLE START OF
INCREASING FLOODING CONCERN ACROSS S FLORIDA
DISCUSSION...AMX RADAR AND GOES-16 1-MINUTE MESO WINDOW VISIBLE
IMAGERY DEPICTS RECENT STRONG RAIN BAND OF MOVE THROUGH
MIAMI-DADE COUNTY EXPANDING SW AND WEST ACROSS THE EVERGLADES WITH
THE TRAILING CONVERGENCE BAND ORIENTING FAVORABLY IN ITS WAKE.
CHARACTERISTICS TO THIS BAND DEPICTED THE STEADILY ERODING MINOR
DRY AIR THAT INTRUDED IN THE FIRST BAND...AS SUCH LESS OF A ROLL
CLOUD/OUTFLOW NATURE WAS SEEN. THIS ALSO WILL KEEP BEST
CONVERGENCE FROM CONFLUENT ENELY TO THE BAND LIMITING NORTHERN
PROPAGATION WITH TIME SUPPORTING AN IDEAL TRAINING PROFILE FOR
UPSTREAM DEVELOPMENT PARTICULARLY ACORS NE MIAMI-DADE/SE BROWARD
OVER THE NEXT 2-3 HOURS. SO FAR A FEW OBSERVATIONS OF 2-2.5"
HAVE BE REPORTED IN BACKYARD MESO-NETWORK OF OBSERVATIONS IN THE
VICINITY OF HST. WITH LESS DRY AIR/TPWS HAVE INCREASED OVER 2.5"
AND WARM CLOUD PROCESSES ALLOWING FOR .5"/HR RATES WITH OCCASIONAL
3"/HR BURSTS (ADDITIONAL .5" TOTAL IN 15 MINUTES). AMX RADAR ALSO
SUGGESTS ADDITIONAL ISLAND INDUCED CONVERGENCE AT THE NORTHERN TIP
OF ANDROS ISLAND...WHICH SHOULD ALSO FOCUS THE BAND FROM WAVERING
TOO MUCH AND ASSIST IN THE TRAINING. GIVEN THE EXPECTED DURATION
OF THIS BAND...TOTALS OF 3-4" ARE POSSIBLE OVER THE NEXT 4-6HRS IN
S FL ESPECIALLY AS INNER BANDS ALSO ENCROACH FROM THE SE.
RADAR/GOES MOSAIC ALSO DEPICTS MOAT BETWEEN OUTER BAND AND NEXT
INWARD BAND IS BEGINNING TO FILL AND ADVANCE TOWARD THE UPPER AND
MIDDLE KEYS...THIS SHOULD START A PROCESS OF INCREASES .5-.75"/HR
STEADY MODERATE WARM CLOUD PROCESS SHOWERS THAT ALONG WITH WIND
INDUCED WAVE/SURGE PROCESSES ARE LIKELY TO START FLOODING ISSUES
ACROSS THIS REGION AS WELL.
GALLINA
ATTN...WFO...KEY...MFL...
ATTN...RFC...SERFC...
LAT...LON 26278003 25938002 25448008 24838058 24448169
24438219 24598235 24708204 24908158 25108130
25438127 25618147 25888150 26168094
Last Updated: 1141 AM EDT SAT SEP 09 2017
|