#42 Postby vbhoutex » Mon Nov 10, 2014 2:35 pm
Here is Jeff Lindner's take from yesterday's email:
Prolonged period of below to well below normal temperatures heading for much of the central and eastern US this week including TX.
Surface high pressure is gradually moving eastward this afternoon with surface winds swinging around to the south and southwest over the area. Winds will increase from the south on Monday and this will result in a fairly warm day with highs in the 70’s across much of the area. Monday will be the last day of highs in the 70’s likely for the next 10-15 days across the region.
US upper air pattern will undergo significant amplification along the US west coast into western Canada and blocking over the Atlantic Ocean in response to the extremely intense extra-tropical cyclone (ex-super typhoon Nuri remains) over the northern Pacific Ocean. Significant ridging along the west coast will dislodge a pool of cold polar air in NW Canada and send in quickly down the front range of the Rockies early this week. The trough being carved out downstream of the ridge over the central US is fairly significant for mid-November with below mid-level heights on the order of 2-3 standard deviations from normal. This will result in a strong polar air mass reaching the US Gulf coast and by Tuesday. Powerful cold front will enter TX Monday evening and sweep quickly off the TX coast Tuesday. Temperatures ahead of the front will be in the 70’s and fall quickly into the 50’s and even 40’s behind the front. Moisture looks fairly meager with the boundary and while forcing will be strong, will not go any higher than 30% for a line of showers mainly toward the coast.
Gusty north winds and strong cold air advection will be in place Tuesday night into Wednesday. Some of the guidance is suggesting a period of about 12-24 hours of weak overrunning clouds as WSW mid-level flow brings moisture over top of the surface cold dome. Any cloud cover will have effects on daytime highs and overnight lows. It is possible that coastal locations could remain mostly cloudy on Wednesday with highs staying in the 50’s. Overrunning regime should end Thursday as deep polar high builds into TX. Clearing skies and lighter winds will result in near excellent cooling conditions Thursday night. With dewpoints in the upper 20’s to lower 30’s a few locations north of I-10 will likely fall to freezing. GFS guidance is showing a low of 29 for Conroe, 32 for College Station, and 35 for IAH Friday morning. Will need to watch this period very closely to see if more widespread freezing conditions are possible. Freezing conditions are likely Friday morning across much of central and north TX.
Cold air will remain locked in place into next week as downstream blocking in the upper air pattern over the Atlantic keeps cold fronts moving southward preventing air mass modification. Undercutting sub-tropical flow and position of the polar highs suggest a fairly potent short wave drops through the mean trough next weekend. With cold air locked in place at the surface mid level moisture will begin to overrun the cold dome on Saturday resulting in increasing clouds and by late afternoon showers developing from SW to NE across the region. Latest GFS run is very aggressive in moisture return late Saturday. Coastal troughing is possible Saturday night into Sunday with rain chances increasing as moisture pours into and over the cold air mass at the surface. This will likely result in very raw conditions by Sunday with highs likely not getting much above 50 with clouds and rainfall. There is some potential for P-type concerns over W/NW/N TX late next weekend where the air will be colder, but all rain for SE TX.
Departing storm system early next week potentially grabs a batch of arctic air over Canada and brings it southward down the plains keeping cold conditions in place through Thanksgiving week as downstream blocking remains in place over the Atlantic.
0 likes
Skywarn, C.E.R.T.
Please click below to donate to STORM2K to help with the expenses of keeping the site going:
