332 AWUS01 KWNH 101337 FFGMPD FLZ000-GAZ000-ALZ000-101800- Mesoscale Precipitation Discussion 0959 NWS Weather Prediction Center College Park MD 936 AM EDT Wed Oct 10 2018 Areas affected...Florida Panhandle & Big Bend, Southwest Georgia, Southeast Alabama Concerning...Heavy rainfall...Flash flooding likely Valid 101334Z - 101800Z Summary...Heavy rain will become more persistent and widespread as Hurricane Michael approaches the Florida Panhandle coast today. Rainfall rates to 3 in/hr will likely lead to flash flooding in some areas. Rainfall totals may exceed 4-5 inches by 1 PM CDT along the immediate coast near where Michael approaches landfall. Additional rainfall would be likely beyond that time. Discussion...Hurricane Michael continues to move toward the Florida Panhandle coast this morning. Some initial low-topped convective clusters and rain bands in the Florida Panhandle have produced around 0.5 to 1.0 inches of rain in 15-20 minutes per several WeatherSTEM mesonet sites. However, these more intense rain rates have generally not been sustained for more than a half hour so far at any specific location as the rain bands have been somewhat discontinuous. That may begin to change over the next several hours as low-level convergence naturally begins to increase over the central Florida Panhandle and Big Bend. This will be due to a combination of speed convergence (as the stronger winds in the inner core begin to approach) and wind direction variation (with winds more backed in the I-10 corridor inland given frictional effects). This may begin to produce some more solid rain bands arcing in off Apalachee Bay, with an attendant increasing risk of flash flooding. Furthermore, the inner core of Hurricane Michael is likely to draw much closer to the coast in the next several hours. Heavy rain bands and eyewall convection should be more sustained in this portion of the storm, which would enable longer durations of heavy rain rates as that reaches the coast. Therefore, through 18Z there will be a small area near the eventual landfall point where rainfall begins to accumulate at a more rapid pace, and totals could exceed 4-5 inches by 18Z. The combination of the arrival of inner core convection and increasing convergent rain bands should increase the flash flood threat in the Florida Panhandle and Big Bend in the next several hours. Further to the north, rain bands will begin to increase in Alabama and Georgia, but flash flooding is less likely there prior to 18Z given the increasing distance from the center of the hurricane and a lack of obvious strong low-level convergence that far north. Lamers ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BMX...FFC...JAX...MOB...TAE...TBW... ATTN...RFC...SERFC... LAT...LON 32188620 32098467 31068342 29828279 28948288 29768401 29488521 30068583 30328652 30278742 31228721