AM Zones Update: More Unsettled Weather, Much Warmer Friday & Saturday

Weather conditions will gradually improve over the next couple of days, as a cut-off low decays and then moves away from the region. But some unsettled weather with possibly some isolated showers or thunderstorms around, will likely continue into this weekend. Much warmer than normal temperatures are still expected for Friday and Saturday. But some cooler weather is likely behind a backdoor cold front for Sunday. More forecast details in a breakdown, into early next week is below.

Today through Thursday

Some showers continue to linger around the region today, as a cut-off low continues slowly moving northward near the New Jersey and Long Island coasts. But the low will be weakening with some mid-level dry air intrusion. So these showers will taper off later this afternoon and evening. Mostly cloudy skies and light onshore winds support highs in the upper 50s to lower 60s, over most of the region today.

Mostly cloudy skies will remain tonight, as much low-level moisture becomes trapped underneath nocturnal inversion.  Some areas of patchy fog could also develop overnight with calmer winds. Temperatures tonight will likely hold steady in the 50s over the region.

The cut-off low will weaken further and either dissipate or move slowly away from the region during the day on Thursday. Light onshore winds will still support low clouds and some fog around, into the morning hours. But more subsidence behind the low, should cause these clouds to mix with more sunshine during the afternoon hours. This will help temperatures into the upper 60s to lower 70s over much of the region.

Thursday night through Saturday

Skies will be partly cloudy Thursday night and Friday morning, as a weakening cold front approaches the region. Some isolated showers or thunderstorms possible, with some weak lift and instability along this front. But this front, will washout with drier westerly winds causing skies to clear for more sunshine Friday afternoon. Temperatures will rise to above normal in the upper 70s to lower 80s, across the region.

Mid-level ridging and drier-westerly winds will support more sunshine for much of Saturday. Temperatures will likely rise into the upper 70s to lower 80s over the region. But models are coming into better agreement with a backdoor cold front moving south through region by Saturday night.

 

Ahead of this front some showers and thunderstorms are possible, Saturday afternoon or evening. Models suggest enough shear and instability with strong mid-level westerly flow moving over the region, for some thunderstorms to become strong or severe with gusty winds. But lack of larger synoptic forcing may keep the region more capped with an EML (elevated-mixed-layer) moving through. So we don’t anticipate most of this activity to be isolated or widely scattered at this time.

These showers may taper off later Saturday, as the cold front pushes further south. Sunday will much cooler day with onshore winds support a maritime airmass over the region. But if cold front pushes far enough south, high pressure just offshore may support more sunshine than clouds. So temperatures may still rise well into the 60s or approach 70 in some spots Sunday afternoon.

Sunday night through Tuesday

Then a storm system associated with a vigorous upper-level trough moving into the Great Lakes, may cause backdoor cold front, to return northward as warm front Sunday night with some more clouds and showers or drizzle possibly returning. If this warm front lifts northward through the region on Monday, then warmer temperatures with some sunshine could return. If it stays farther south, it will remain cloudy and cooler for much of the region. At this time, we remain skeptical on the northward progress of the warm front, due to departing high pressure, off the New England coast, supporting more onshore winds.

But a stronger cold front with the upper-level trough from the west will likely move through sometime late Monday or Tuesday. Large scale forcing, lowering heights and strong wind fields will likely support more numerous showers and thunderstorms during this period. There is potential for some heavy rainfall with plume of subtropical moisture feeding into system. Some strong or severe thunderstorms are possible, dependent on the frontal timing and amount of instability.

A cooler airmass moves in, behind this storm system for middle of next week. But these temperatures appear to just closer to seasonal levels over the region. The coolest temperature anomalies are likely to more underneath deeper troughiness or lower heights over  the Great Lakes/Ohio Valley regions for next week. Stay tuned for more  zone forecast updates over next couple days on the weather through this weekend and into next week!