Area Forecast Discussion
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000 FXUS61 KPBZ 151757 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1257 PM EST Thu Feb 15 2018 .SYNOPSIS... A warm front will keep light rain chances through this morning before low pressure and a cold front results in widespread rain later today and tonight. Precipitation should taper off Friday as the front exits. && .NEAR TERM /THROUGH TONIGHT/... With noon update, tweaked hourly pops as most of the region remains dry, except for locations south of Pittsburgh. Primary area of rain is currently across Indiana and western Ohio, but is continuing to make eastward progress. Previous... The sfc low and associated shortwave is progged to track to the Upper OH Valley region by late afternoon/evening, spreading widespread rain across the area. Jet enhanced ascent, good upper support and deep layer moisture should result in enhanced rainfall rates this evening and overnight. Expanded the flood watch further N and W based on the latest guidance and expected rain totals. Several river flood watches also continue for the Monongahela and Ohio rivers where the highest QPF is progged. The low is progged to slide E to N Cntrl PA late tonight, as it drags its associated cold front across the area. Temperatures today and tonight should be 20-25 degrees above seasonal levels. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... The cold front should complete its passage Friday, with precip chances tapering off after FROPA. A brief changeover to snow is possible as the precip ends, but little or no accumulation is expected. Dry weather should return Friday night and Saturday morning as high pressure slides E across the region. Models continue to struggle with a cold front advancing across the Upper Midwest later Saturday, and sfc low pressure across the SE CONUS. The 00Z GFS doesn`t phase these two features, while the 00Z NAM briefly does before exiting the E coast. The ECMWF was the most aggressive with the phasing, resulting in more precip across our region. Expect the middle of the road NAM solution is the most reasonable, which would result in some mainly light snow chances to the area later Sat/Sat night. High pressure should return dry weather for Sunday. Temperatures should be near to a few degrees above seasonal levels. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... Southwest flow between a Wrn CONUS trough, and a SE CONUS high should result in warm weather through the period. Shortwaves embedded in the flow, and proximity to a slow moving frontal boundary, should keep periodic rain chances through mid to late week. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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High MVFR/low VFR cigs will persist for another hour or two before conditions deteriorate with the approach of an upper level shortwave. Rain will begin to spread into the region over the next couple of hours, with temporary vsby restrictions until the heavier precipitation reaches the area this evening. Made most of the adjustments to the terminals based on the placement of the heavier precip in the hi res model guidance. Still expect a period of IFR almost everywhere overnight as lift and thus precipitation rates are enhanced with the passing cold front. Improvement to MVFR is expected behind the front passage tomorrow though scattering out of the clouds is not likely until late. A wsw to nw wind shift will occur overnight. Gusts to 20+kts are possible tonight and Friday.
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&& .HYDROLOGY... Widespread moderate to heavy rain should overspread the area this aftn and tonight as low pressure and a cold front approaches and crosses the area. Rainfall amounts are expected to range from around an inch N of I 80, to around 2 inches across the OH and Monongahela basins. The flood watch has been expanded N and W and various river flood watches for specific points along the Ohio and Mon rivers continue. The point at Pittsburgh is expected to rise to 18 ft Fri morning which affects the Mon Parking Wharf, and above flood stage, 25 ft, Sat morning. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...Flood Watch from 6 PM EST this evening through Friday afternoon for MDZ001. OH...Flood Watch from 6 PM EST this evening through Friday afternoon for OHZ039>041-048>050-057>059-068-069. PA...Flood Watch from 6 PM EST this evening through Friday afternoon for PAZ014-020>023-029-031-073>076. WV...Flood Watch from 6 PM EST this evening through Friday afternoon for WVZ001>004-012-021-509>514. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.