Mailman

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... A prolonged period of wintry impacts is expected Monday into Tuesday as a series of shortwaves within southwest flow move across the Upper Ohio River Valley. The first, weaker wave will see spread mainly snow over the area Monday morning, with precipitation enhancements north and west of Pittsburgh due to a strengthening upper jet and strong frontogenesis stretching from SW to NE OH. Slight warm advection will create more of a wintry mix generally southeast of Pittsburgh. After a very brief break late Monday aftn due to shortwave ridging, the second and more potent shortwave will cross the region Monday night into Tuesday. Model trends have brought the upper trough and 850mb low farther west, allowing for better warm air intrusion to the southeast of the low. If this holds, snow will be the predominant precipitation type along the I-80 corridor and east of I-77, transitioning to a combo of snow/sleet/freezing rain along the I-70 corridor (including Pittsburgh) and sleet/freezing rain/rain for northeast WV. Any shift in the 850mb low track west (east) will draw that change over line farther northwest (southeast). The combination of a strong, coupled jet, strong mid-level frontogenesis, and varying but cold enough thermal profiles, have issued a Winter Storm Warning. The warm air intrusion will likely limit snow/ice accumulation for portions of northeast WV, thus a Winter Weather Advisory was issued. Precipitation will generally dissipate through the day Tuesday as the low and sfc cold front move east of the region and a notable dry slot develops within the wake of the exiting shortwave. Cold advection will ensue as the longwave trough axis moves overnight Tuesday night, dropping area temperature well below seasonal averages.

Yeah.. I deleted it. Don't know why it won't show the correct one when you paste a direct link to the graphic.

Don't shoot the messenger.

Ron Smiley'd...

Freezing Fog is no joke.

18z HRRR looks good after wave 1.

Oh boy.

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... A series of shortwaves withing SW flow will increase wintry precipitation chances Monday into Tuesday as the longwave central U.S. trough axis shifts slightly eastward. At the sfc, a low will develop and deepen as it moves from the Mississippi Delta towards the northeast U.S., with cold air filtering into the region Tuesday as it moves farther east of the Upper Ohio River Valley. Confidence remains high in accumulating snowfall for much of the region and the second wave late Monday into Tuesday being the more significant punch. The combination of colder air, strong frontogenetic forcing and jet support will help produce potentially heavy snow around and to the north/west of Pittsburgh, a Winter Storm Watch was issued. Additional headlines are likely for the rest of the region as confidence increases in the timing and the type of impacts expected. That said, granular details for each wave remain inconsistent between models and from run to run for both incoming waves. Among the varying details through the event include positioning of a mid-level frontogenetic zone; strength of ascent and associated connections to a briefly coupled jet; strength and shifting of a baroclinic zone southeast of Pittsburgh leading to more of a wintry mix or freezing rain; efficiency of freezing rain accumulation; and potential dry slotting within the SW flow reducing accumulation efficiency. Increasing sfc high pressure and shortwave ridging will develop in the wake of the exiting shortwave/low Tuesday night, with single digit temperature likely for most locations.

Canadian appears solid.

.LONG TERM /MONDAY THROUGH FRIDAY/... The sw flow over the Upper OH is forecast to continue next week with a series of crossing shortwaves within flow defining precip chances, the most significant indicated for Tuesday. With plentiful boundary layer moisture evident in relatively warmer swly flow, ascent provided from a northern stream open wave, assisted by coupled jet and coincident near sfc frontogenesis will prime the region with the ingredients necessary for a widespread precipitation event on Tuesday. While longer range solution output varies in terms of snow accumulations (GFS vs. ECMWF), a couple of considerations should be noted. The first is that both models indicate the location of the mid-level low west and north of the forecast area. With the region located within the warm sector, this would imply the potential for a wintry mix across portions of the region (especially south of I-80) as warm advection hinders overall snow growth efficiency and introduces other hazards such as sleet/freezing rain. GEFS plumes for PIT hint at this hindrance as the operational GFS snow accumulation output is much higher than majority of other members. Other considerations include the anticipated quick progression of the storm which implies a rather progressive, open wave in conjunction with anticipated dry slotting. This translates to precipitation diminishing rather rapidly later Tuesday. Nonetheless, hazardous wintry weather should be anticipated, especially early Tuesday, and headlines may be required. This will bear watching through the course of the weekend with more updates to follow.

GFS puts me back into a nice amount of the white stuff.

.LONG TERM /MONDAY THROUGH THURSDAY/... The southwest flow ovr the Upr OH is forecast to continue next week with shortwaves within flow defining precip chc, the most significant indicated for Tuesday. Current depictions are for the mid level low to dig toward the Great Lakes, thus limiting snow and overall precip potential via warm advection and dry slotting. Still, mixed precipitation including freezing rain is expected with such a scenario, development which will have to be monitored.

GFS right where we want it 5 days out.

GFS did come a little east.

It has begun.

Canadian looks alright for next week.

0z GFS seems as though it's gonna deliver the goods again.

GFS coming in hot D6.