Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Sep 14 2023 01:16:42 AWUS01 KWNH 140116 FFGMPD MEZ000-140630- Mesoscale Precipitation Discussion 1068 NWS Weather Prediction Center College Park MD 915 PM EDT Wed Sep 13 2023 Areas affected...Maine Concerning...Heavy rainfall...Flash flooding possible Valid 140111Z - 140630Z Summary...Showers with embedded thunderstorms will continue a threat for flash flooding across portions of ME through 06Z with rainfall rates up to 1.5 in/hr. The threat is expected to translate northeastward with time but there's a low end chance of the flash flood threat building southward toward the coast. Discussion...Local radar imagery from KGYX showed an axis of heavy rain over west-central ME at 01Z, oriented from SSW to NNE near the Kennebec River Valley. Peak MRMS-derived hourly totals have ranged between 1 to 1.5 inches within this axis, confirmed by local automated gauge reports near Farmington recently reporting 1.3 in/hr rainfall rates. An axis of low level moisture convergence was supporting the region of heavy rain, situated just ahead of a weak 925-850 mb low estimated to be over northwestern ME at 01Z per area VAD wind plots, and a related surface trough axis. 20-30 kt of low level flow was focused just ahead of the low/trough, co-located with an area of weak MLCAPE that ranged between 100 and ~500 J/kg per SPC mesoanalysis data and the 00Z GYX RAOB. While instability is expected to slowly weaken overnight, anomalous precipitable water values (1.5" at GYX, above 90th percentile for this date) will continue to advect northward into central ME, continuing to support areas of training along the low level convergence axis as it translates northeastward. Farther south, while there isn't a good signal in recent hires guidance, there is a low chance that heavy rain develops and focuses near the coast within the moisture plume as the entire state will be situated beneath the favorable right-entrance region of a 90-100 kt jet max located east of a parent upper trough over western Quebec. Peak rainfall rates of 0.5 to 1.5 in/hr are expected which would exceed area FFG of 1 to 2 inches in 1 hour. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_2QBZIUHlnKfEtTDjZJemvb09Luwm8jcDn4Qu2h7xFGok9qhipEuH7YGEiMtwyhR7Vbs= WhQZ-FLh2qbdxWml33jp_pY$ for graphic product... ATTN...WFO...CAR...GYX... ATTN...RFC...NERFC...NWC... LAT...LON 47056878 47026828 46546792 45856777 44316846=20 43296964 43487058 44397039 45627009 46266972=20 46806925=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .