Wednesday begins much like it has the past three days with areas of fog possible to start off which burns off in most areas by mid-morning.
The humidity levels that have brought some parts a heat index over 90° will remain through the day. Cloud cover from a slow moving frontal boundary from the northwest will help keep temperatures down a few degrees, but it may hardly be noticeable over most of the region.
The Storm Prediction Center indicates that the crown of the state into the western mountains is at marginal risk for severe weather, with damaging winds possible in stronger storms.
The state appears mainly dry for most of the day. There could be an isolated storm for northern areas in the afternoon, but showers and storms aren’t expected to increase until around the 6 PM hour.
Showers and storms remain widely scattered through the evening, By midnight, what is left of any convective energy begins to dissipate, which will reduce the severe storm threat.
By daybreak on Thursday, showers appear to have ended over northern areas, and the rest of the state sees any shower activity end by mid-morning.
Behind the front, an northwest breeze sets up, bringing with it much drier air, and cooler temperatures. By noon time, dew points are forecast to fall into the 40s over much of the state.
All in all, not a whole lot rain expected with this frontal passage. Amounts may vary pending on any heavy downpours over the western and northern parts of the state. Southern Maine may see a widely scattered shower out of this, but little, if any rainfall is expected.
Canadian high pressure takes over the weather pattern for the state into the middle part of next week. With the clear skies and cooler temperatures aloft, the risk of frost lingers for the mountains and north.
A look at numerical data from the Tuesday 12z GFS model runs shows the down trending temperatures aloft and and the surface. This is looking at the projected temperatures at the Greenville Airport observation station through early next week. Temperatures in Celsius go from an anomalous high 18.4°C (65°F) as of 8 AM Tuesday to a below normal -2.6° (27°F) by 8 AM Saturday at the 850 MB (~5,000 ft) level. This translates 2 meter temperatures ranging from 69° at 8 AM Tuesday to 34°F for 2 AM Saturday and 33° for 2 AM on Sunday, respectively. With the thickness levels listed in the far right column flirting with the 540 benchmark level for a freezing level, frost is certainly in the discussion for western and northern areas this weekend.
A look at the map chart of projected surface temperatures Saturday morning, it shows areas that could fall to freezing or below. It should be noted that the GFS model has a known cold bias to it. For those who have late season crops in the foothills of western areas on up through the rooftop of the state, be aware that the threat is there both mornings over the weekend.
For you early morning travelers, be aware of patchy fog around lakes and rivers due to the much cooler temperatures through Monday.
Special thanks to Weather.us for use of their forecast charts.
Always Stay Weather Aware!