Cold Front To Bring Heavy Rain, Cool Temps Sunday Night

Hello everyone!

Slightly more humid air is beginning to filter into the region today ahead of a cold front that will bring showers to the area Sunday night. Some of those showers could contain a rumble or two and may produce heavy rain especially north. Cool, dry air floods in for Monday and Tuesday before SW winds slowly increase both temps and humidity through next weekend. Our next chance for precip arrives next weekend with the passage of a weak front.

4:30 PM Observations Verifying Today's Forecast
4:30 PM Observations Verifying Today’s Forecast

Today’s forecast wasn’t super awesome. The biggest issue was cloud cover. A layer of marine stratus/fog developed over the waters from Portland NE through the midcoast. This stratus layer moved onshore over the midcoast bringing overcast conditions. This mistake was due to an underappreciation for dew points to the south that advected northward on SE winds that developed as high pressure slid offshore. Otherwise, most areas saw some sun as temps rose into the 70’s to low 80’s as expected. Overall, not a super great day but definitely not a disaster.

Current 4:30 PM WV Satellite Showing The Setup For Sunday Night. Image Credit: COD
Current 4:30 PM WV Satellite Showing The Setup For Sunday Night. Image Credit: COD

Water vapor imagery shows the setup for the next few days perfectly. A plume of moisture extends from tropical storm Kay (not pictured) in the Eastern Pacific to a storm over Wisconsin. Cool, dry air is streaming south into the Northern plains. Along the boundary between the two, showers and storms are ongoing (storms are anomalously bright spots). This whole system will slowly shift east tomorrow, eventually reaching us by tomorrow night.

12Z 4km NAM Showing What The Radar May Look Like Early Monday Morning. Image Credit: Weatherbell
12Z 4km NAM Showing What The Radar May Look Like Early Monday Morning. Image Credit: Weatherbell

What will it look like when it gets to us? The answer will depend on location. A line of weakening thunderstorms is likely to impact Southern New England with the far northern edge of that line moving through S NH and far SW ME. For southern areas, this is where the show begins and ends. The line of showers could contain a couple of rumbles but will be narrow and won’t have enough time to drop a soaking rain. Farther north, a steadier rain is likely. It won’t quite rain as hard here but it will rain for longer which will be enough to drop a more substantial rain. The timing for all of this will be in the wee hours of Monday morning. The map is valid for 5 AM.

12Z GEM Showing The End Result Of Sunday Night's Rains. Image Credit: Weatherbell
12Z GEM Showing The End Result Of Sunday Night’s Rains. Image Credit: Weatherbell

The end result will be more rain in the north and less in the south. The GEM represents the lowest end of the guidance envelope in terms of total precip but based on the pattern of recent events disappointing, the low side is what looks most reasonable. A quarter to half inch of rain is likely for the south and east while the north and west sees between a half and one inch of rain. While this will certainly help the drought, it still won’t be enough to bust it. We’d need a good 4-8″ rain to finish that job.

12Z GFS Showing The Pattern For Mid/Late Week. Image Credit: Weatherbell
12Z GFS Showing The Pattern For Mid/Late Week. Image Credit: Weatherbell

Showers will depart Monday morning around sunrise and gusty NW winds will bring in cooler and drier air for Monday afternoon through Tuesday. High pressure will shift offshore Tuesday and between it and a front to the NW, SW winds will begin to slowly bring warmer and more humid air into the region. By Friday it will again feel sticky with temps near 90 and dew points in the 60’s. The front will cross the region at some point next weekend bringing another chance for showers and possibly a few storms.

This evening’s tropical update can be found on the newly minted tropical weather page. Check it out for links to tropical weather information from the NHC as well as my forecasts and tools to look at tropical weather data for yourself!

More tomorrow.

-Jack

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