Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Nov 22 2022 18:58:48 ACUS01 KWNS 221858 SWODY1 SPC AC 221857 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 PM CST Tue Nov 22 2022 Valid 222000Z - 231200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Showers and a couple of thunderstorms with gusty winds are possible late this afternoon across southern Washington and northern Oregon coastal areas. Otherwise, the risk for thunderstorms remains negligible across much of the remainder of the U.S. through tonight. No updates were made to the existing outlook. ...Jewell.. 11/22/2022 ..PREV DISCUSSION... /ISSUED 1015 AM CST Tue Nov 22 2022/ ....Synopsis... Amplification within one belt of westerlies across the mid-latitude Pacific is underway. This is forecast to include large-scale mid-level ridging building across the eastern Pacific, toward the North American coast, later today through tonight. As this occurs, a vigorous downstream short wave trough appears likely to rapidly dig inland of the Pacific Northwest coast by early this evening, and into the Rockies by daybreak Wednesday. Another perturbation is expected to continue digging within a separate branch, across the subtropical eastern Pacific to the west of Baja. Models indicate that flow farther downstream will remain broadly confluent east of the Great Plains through the Atlantic Seaboard. Beneath this regime, although it may continue to slowly weaken, cold surface ridging appears likely to persist across much of the southeastern U.S. into the northwest Gulf coast vicinity. Weak moisture return may commence above this air mass across the lower Rio Grande Valley into parts of the southern Great Plains, and perhaps near southern Atlantic coastal areas. Otherwise, appreciable boundary-layer moistening may remain confined to parts of southeastern Florida, as northeasterly to easterly near surface flow is maintained across the peninsula and northern Gulf of Mexico. ....Pacific Northwest... Low-level moistening maintained in the wake of an inland advancing surface front may be sufficient to contribute to weak boundary-layer destabilization, in the presence of substantive post-frontal mid-level cooling (including 500 mb temps falling to around or below -26C). It appears that this may become supportive of low-topped convection capable of producing at least some lightning across southern Washington/northern Oregon coastal areas by 21-22Z, near or in the wake of a small but rather intense mid-level jet streak (including 70-90+ kt around 500 mb) migrating inland. Given forecast soundings exhibiting 30-40+ kt westerly mean flow in the lowest few kilometers above ground level, locally strong wind gusts aided by downward momentum transfer may be possible in the more vigorous showers/storms. However, activity is still expected to generally remain below severe limits. $$ = = = 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) .