Tuesday 9 a.m.
Yesterday, the Buffalo area had snow flurries. Tomorrow, the temperature will top 70. Yesterday started with frost in some Chicago suburbs; today, it's going to middle 80s. And, at Goodland Kan., where they had almost 4 inches of snow on May 1, it was 92 yesterday! The heat in the middle of the nation will lose some of its steam on the way east, but at Saranac Lake, N.Y., this morning's low of 24 will replaced by 64 tomorrow afternoon.
An energetic low pressure area west of Winnipeg this morning will vault past Vermont by Thursday morning. Winds have gusted past 40 mph in the Dakotas this morning. One concern is that with the warm air blasting northeast while the upper air temperature rise moderately, the stage is set for gusty thunderstorm development. These could affect parts of the Great Lakes tonight and the area from New York to Virginia tomorrow.
On this map, you can see the large area of southwesterly flow that's advancing eastward. This flow is bringing in much warmer air.
Last week, I mentioned that longer range computer models were suggesting a major warmup by next weekend. More recent runs have backed off on the that idea. However, there is extreme uncertainty beyond the next 7-10 days. This can be seen by looking at the following map.
n the forecast office, we often track cold fronts with pressure maps like these. The examples are from 4AM and 10 AM today. You can see that the northern part of the front is moving more quickly than the southern end. The arrival of the front signals the start of the cooling trend that is spreading east.
The upper air flow over the East is from the west-southwest now, and some of the moisture associated with the cold front can be traced back to tropical storm activity off the Mexican west coast last week. The same moist air mass set the stage for recent flash floods in Arizona. By early next week, the upper-air flow will be coming to the Northeast region from well up in western Canada, as seen on this forecast map forecast map for next Tuesday:
As chilly air pours into the northern Plains and backs into the Rockies, snow can break out at higher elevations. Gillette, in northeastern Wyoming at an elevation of just over 4,000 feet, could have a close shave with snow on Thursday. This map shows the setup.
The main U.S. computer model shows very cool air coming into the Northeast this coming weekend. However, the same model shows a complete reversal by the following weekend.
Meanwhile, it is warm and humid in the Northeast corridor today but should be much more comfortable on Sunday. This map shows the pressure and temperature setup that existed at 7 a.m. ET. The cold front is associated with the rapid change of shape/direction in the pressure contours over the upper-left part of the map.