High pressure from Canada in building into the region today. Scattered showers with a cold front have pushed south of the region this morning. Clouds are breaking for sunshine this afternoon. High temperatures will be in the upper 40s to lower 50s. Which is near normal for this time of year. Winds will be light out the north.
Mostly clear skies and light northeast winds expected for tonight. This will allow for radiational cooling many areas tonight. Low temperatures by sunrise will be in the upper 20s to lower 30s in New York City and coastal sections. Lower to middle 20s in the inland areas and the pine barrens.
High pressure will gradually shift to the northeast Friday night and Saturday. Clouds will increase on Friday night. An amplifying ridge over the Western United States, will cause shortwave energy to dig and form into closed upper-level low over the Ohio Valley/Great Lakes. This will cause a double-barbell surface low-pressure system to organize over the Eastern US on Saturday. A deep southerly flow will transport a plume of moisture from the Gulf of Mexico and the Atlantic into our area. Most of the model guidance agrees on a widespread heavy rainfall throughout the area starting during on Saturday and continue into Saturday night. Saturday will feature mostly cloudy and skies with some intermittent rain and drizzle breaking out from southwest to northwest across the region, during the morning and early afternoon hours on Saturday. A strengthening southerly low-level jet and precipitable water values approaching two inches will cause rain to become steadier and heavier at times, late in the afternoon and early Saturday night for the region. Some of the model guidance shows some elevated instability. So there will there could also be isolated thunderstorm as well. Rainfall totals in excess of 1 or 2 inches are possible and could be enough to cause some flooding in poor drainage or low-lying areas. As surface low pressure and dynamics shift north of the area, rain will begin taper off to lighter showers late Saturday night.
Mostly sunny skies are expected today. But it will be not be as warm as than yesterday. With high pressure centered to the east, winds will be more out the east to southeast direction off the colder waters. High temperatures will reach the lower to middle 60s over inland areas. Upper 50s to lower 60s are more likely for high temperatures closer to coast. A weak shortwave trough advancing from the west will increase clouds tonight. Some scattered showers are likely around the area, late tonight and tomorrow morning. Forcing and moisture is limited with this system. So rainfall amounts should be mainly on the light side. High temperatures are expected to be in the middle to upper 60s, with winds more out the southwest with cloud cover.
Yesterday’s temperatures reached the lower 70s. Despite northerly winds and 850mb temperatures of only 4C – 5C during the afternoon. This was due to a downsloping and a deep mixed-layer. Which caused the dewpoints to drop and more dry-adiabatic heating to occur. Model guidance has 850mb temperatures around +8C on Saturday afternoon with a west to northwest downslope flow. This mean high temperatures in the middle to upper 70s, across much of the area. It’s not out question some spots reach 80 degrees. The soundings actually show a deep-mixed layer above between 800mb-850mb, Saturday afternoon. Which often supports temperatures several degrees warmer than model guidance shows.
0z NAM showing widespread 70s over region on Saturday
High pressure will slide off the coast on Sunday. This will cause winds to turn more out of southeast off the cooler ocean. Temperatures will not be as warm as on Saturday. Highs will only reach the lower to middle 60s, away from the shore. Sunday will still be mostly sunny and dry as high pressure will remain in control.
The northern and southern will phase into large upper-level low over Great Lakes region, early next week. A frontal system will move across the area on Monday. A strong southeasterly flow ahead of front, will bring moisture into the region. Model guidance is converging on a triple-point low developing along this front and a 40-50kt 850mb southerly jet moving across the area. These features will enhance more lift, moisture, and some elevated instability over the area on Monday. Precipitable water values between 1.00″ – 1.50″ support widespread rainfall totals over 1″. The pressure gradient between low and the high offshore could also gusts to 40mph, near the coast on Monday. With the new moon this weekend and early next week, this could result in some minor coastal flooding at high tides as well. We are talking about potential, at this point. These details will be fine tuned as we get closer to this event.
0z GFS showing 40-50kt 850mb jet over the Tri-state area on Monday
Unsettled weather pattern remains after this system, with the large upper-level closed low remains over Great Lakes and a ridge building over Hudson Bay and Davis Strait. A number systems may be coming around this low over the Eastern US. This means weather conditions are likely to vary from day to day. Dependent on timing, some days could still be warm and sunny Other days could be cooler and wetter. As often the case, we will have better idea on the weather each days, as we get closer/
Miguel Pierre Weather 