833 FOUS62 KALR 221406 FFGSJU COUNTY FLASH FLOOD GUIDANCE...PUERTO RICO NATIONAL WEATHER SERVICE SOUTHEAST RIVER FORECAST CENTER...ATLANTA GA 1005 AM EDT SAT AUG 22 2026 INCHES OF RAINFALL FOR SPECIFIED DURATIONS REQUIRED TO PRODUCE FLASH FLOODING IN FORECAST ZONES. LOWER AMOUNTS MAY CAUSE FLASH FLOODING IN URBAN OR MOUNTAINOUS AREAS. .B ALR 20260822 Z DH12/DC202608221405 /DUE/PPHCF/PPTCF/PPQCF :IDENTIFIERS ARE 2-LETTER STATE, Z FOR ZONE, 3-DIGIT ZONE NUMBER : :IDENT 1HR 3HR 6HR ZONE NAME :======= ==== ==== ==== ==================== PRZ001 1.9/ 3.6/ 4.9 PRZ002 1.9/ 3.6/ 4.9 PRZ003 1.9/ 3.4/ 4.8 PRZ004 1.9/ 3.4/ 4.8 PRZ005 1.6/ 2.2/ 2.9 PRZ006 1.6/ 2.2/ 2.9 PRZ007 1.6/ 2.2/ 2.9 PRZ008 1.6/ 2.2/ 2.9 PRZ009 1.6/ 2.2/ 2.9 PRZ010 1.6/ 2.2/ 2.9 PRZ011 1.6/ 2.2/ 2.9 PRZ012 2.0/ 3.2/ 4.5 PRZ013 2.0/ 3.2/ 4.5 VIZ001 2.1/ 3.3/ 4.6 VIZ002 2.1/ 3.3/ 4.6 .END $$ S.E.R.F.C. 770-486-0028 or 770-282-2112 Regular Hours 6am-10pm Eastern Time After Hours Please Follow Callback Instructions  806 AWUS01 KWNH 221450 FFGMPD DEZ000-MDZ000-VAZ000-222030- Mesoscale Precipitation Discussion 1111 NWS Weather Prediction Center College Park MD 1049 AM EDT Sat Aug 22 2026 Areas affected...Middle to Lower Chesapeake Bay Region... Concerning...Heavy rainfall...Flash flooding possible Valid 221450Z - 222030Z SUMMARY...Slow moving/training warm-cloud efficient rainfall production to 2.5"/hr pose localized flash flooding with 2-4" totals in 1-3hrs. DISCUSSION...GOES-E WV and Regional RADAR shows a shortwave feature moving northeast in the warm conveyor belt southeast of the tip of the Delmarva Peninsula; while the expanding right entrance region of a 80-90kt 300mb jet remains directly overhead. This direct circulation is tightening (FGEN) a SW to NE convergence/deformation zone across South-central MD into southern DE. An axis of modest but sufficient low level unstable air existed through the lower Chesapeake Bay with a wedge of 1000 J/kg of MUCAPE residing along this axis of deep layer moisture convergence. As such, shallow thunderstorms developed across Charles to N Calvert county and extend through the Bay toward Talbot county. The shallow nature though with solid moisture flux through channeling up the Bay supports efficient tropical/warm-cloud rainfall production to support 2-2.5"/hr rates. In addition, localized frictional convergence along the edges/inlets of the Bay has resulted in more scattered/isolated but equally efficient heavy rainfall producing cells. Deep layer steering and fairly stationary right entrance region suggest slow forward propagation through the Bay toward the Eastern Shore over the next few hours. Observations so far of 1.5 to 3" in about 60-90 minutes and while the area is fairly sandy in soil type, MRMS Flash response is reaching 200-300 cfs/sqmi suggestive of localized flash flooding may be starting soon. Hi-Res CAMs all generally show a core of 2-4" additional totals through 21z, mainly focused directly over the Bay and nearby coastal areas, though some solutions hint of higher localized totals of 5"+ as well, suggesting flash flooding will remain possible into the afternoon hours across the Delmarva Peninsula, Southern Maryland and the northern Neck of VA. Gallina ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...AKQ...LWX...PHI... ATTN...RFC...RHA...NWC... LAT...LON 38917573 38667525 38287505 37747541 37497564 37467600 37797669 38177699 38567702 38907660