Issued: 1pm on Sunday, January 24th 2021
Technical Forecast Discussion
Short Term (Sunday 1-24-2021 through Tuesday 1-26-2021)
PDVA and low level WAA will continue to stir up clouds and precipitation across the forecast area Sunday. This precipitation will fall mainly in the form of snow showers and freezing rain showers. This precipitation will be quite light and will have quite a low impact on the forecast area Sunday. Strong NDTA will continue to build ridging into the forecast area throughout the short term. This will have major impacts on potential systems that will try making their impacts on the forecast area over the next 48-72 hours. Out west, a strong VORT max that has been sitting and spinning over southeastern California and western Arizona will begin opening up and propagating eastward due to stronger VORT on the south end of the feature. As this slopes down the mountains into the Plains, VORT will be stretched vertically, and cyclogenesis will occur along a temperature gradient east of the mountains where upper DIV at the left exit of a jet streak meets this temperature gradient (likely over southwest Texas). Frontogenesis will occur as well, where centrifugal forced upper DIV occurs. This low will follow its forcing along the jet streak. The previously mentioned strong NDTA downstream of this will be much stronger than PDTA upstream, preventing this from becoming a high amplitude system, and weakening it in the process. The surface cyclone will still continue to follow its forcing up into the Ohio River valley by Monday night. WAA and PDVA will generate sufficiently negative omega for precipitation, mainly in the form of rain, across the forecast area. Snow will be the most likely along and north of the I-76 corridor. The precipitation will spread in Monday morning and last through late Monday night. As the system fills, precipitation forcing for omega will no longer be sufficient for precipitation generation, and skies will begin to clear out by early morning Tuesday. Highs Tuesday should be in the middle and upper 30s with cloudy skies clearing out throughout the day on Tuesday. Back west, another deep trough will make its way into California. This will reach New Mexico and Texas by Tuesday night into Wednesday.
Long Term (Wednesday 1-27-2021 through Saturday 1-30-2021)
While Monday and Tuesday’s system will slightly erode the ridging in place, strong NDTA will keep ridging over the forecast area through much of the day Wednesday. Mainly cloudy skies should remain in place for Wednesday, as PDVA remains over the forecast area during this time. Highs Wednesday should remain in the lower and middle 30s as influence from an arctic cold core high at the surface will advect cool temperatures into the forecast area. As another trough enters the CONUS Monday night, PVA will continue to propagate it eastward, and eventually allow this to end up in southwest Texas. Once again, as this VORT slopes down the Rockies, and upper level DIV at the left exit of a jet streak moves over a temperature gradient east of the Rockies, cyclogenesis (this time a little further east than the last time) will occur over the southern Mississippi valley Wednesday morning. This will follow a more zonal forcing than last time, into the Tennessee valley. PDVA and WAA throughout the afternoon Wednesday will stir up negative omega to produce snow showers, lasting through early Thursday morning. Accumulations from this system will be light, and mainly across southern Ohio. The remainder of Thursday should be mainly cloudy with highs in the upper 20s and lower 30s. PVA will continue to propagate this feature eastward into the Atlantic. As this occurs, NVA and strong NDTA will build in more high amplitude ridging into the forecast area Friday into Saturday. With WAA in the low levels, NDTA will not be enough to keep skies clear throughout Friday and Saturday. Due to phase lagging, temperatures will remain in the upper 20s and lower 30s on Friday. Saturday, temperatures will reach the lower and middle 30s. Another trough entering the CONUS Friday will propagate into the Rockies Friday night into Saturday. As this reaches downslope of the Rockies Saturday morning, vertical stretching of aloft VORT, and aloft DIV will drive cyclogenesis yet again over the plains, This time over Kansas. FGEN occurring because of aloft DIV due to changes in the centrifugal force will drive a possible snow band along the warm front late Saturday night. A quick 1-3″ of accumulation could be possible with this–stay tuned