April 18, 2013: Fri Night Storms, Then Cooler

Reminder: Daily updates will resume starting tomorrow, on Friday, April 19.

Forecast Highlights:

Temperatures today will be slightly cooler than yesterday, mostly peaking in the mid 50s to low 60s, but with 70s expected to return for Friday followed by a cold front overnight producing heavy rain, thunder and wind. Cooler temperatures are expected to return by the weekend, with rain again expected for early-mid next week but with the cooler than average temperatures to continue as well.

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Today - Friday Night: Mild, Then Storms

As of this morning, temperatures were in the mid to upper 50s east of NYC and in the upper 50s to low 60s from NYC and further west. Mainly cloudy skies are expected with isolated showers at times, with highs peaking in the upper 50s in Long Island/S CT, and in the low 60s from NYC and further north/west. Mainly cloudy skies will continue tonight with temperatures initially steady around the mid 50s, then rising slowly into the upper 50s to low 60s by Friday morning.

With the warm front well to the north of the region on Friday, warmer temperatures will cover the majority of the region, with 70 degrees extending as far north as northern New England. Mostly cloudy skies are expected for the area with a breezy south wind gusting up to 30-40 mph as temperatures warm into the low to mid 60s near the eastern coastal areas, mid to upper 60s in Long Island/S CT away from the coast, low 70s in NYC and the low to mid 70s north and west of NYC.

The strong cold front currently producing widespread severe weather in the Ohio Valley will move through the region in a weakened form on Friday, still producing heavy rain and thunderstorms but with severe weather less widespread. The line of storms is expected to reach the area towards 8-10 PM west of NYC and 10 PM-12 AM east of NYC, mostly remaining non-severe with a lack of instability, but still producing locally heavy rain and capable of strong wind gusts with high bulk shear and a relatively strong low level jet. The rain will clear most of the area by 5 AM after at least 1/4 to 1/2 inch falls, locally higher, with partly cloudy skies expected for Saturday morning.


Weekend - Next Week: Cooler Temps, Rain Returns Mid-Week

Another trough will enter the region by Saturday, providing the region with dry and cooler conditions for the weekend. Saturday is expected to be partly cloudy with highs in the mid to upper 50s for interior north/west areas and the upper 50s to low 60s for the rest of the area. Cold temperatures are expected overnight with lows falling into the mid to upper 30s across the entire area and likely dropping to near or below freezing in interior CT, SE NY and NW NJ, where frost is possible. With a strong high pressure overhead, Sunday will be sunny with highs reaching the low to mid 50s inland and the mid 50s for the rest of the area.

By Monday, ridging will build aloft, but with the surface high pressure to the northeast of the area, an east flow will develop with temperatures remaining cooler than average, peaking in the low to mid 50s east of NYC and the mid to upper 50s from NYC and further north/west, with partly to mostly cloudy skies and isolated showers. Previously, the ECM was the only model suggesting a significant coastal low would develop with widespread heavy rain, and as of this morning has largely backed off this idea, now siding with clouds and isolated showers but no organized storm for Tuesday. At least a weak low pressure is possible offshore on Tuesday which would result in mainly cloudy skies and scattered showers especially east of NYC, with highs again mostly in the low to mid 50s range.

The next significant low pressure will track through the Midwest on Wednesday, with its cold front moving through the region around Wednesday night and Thursday. The GFS is the fastest with the frontal passage, bringing the front through during the day on Wednesday; accounting for the GFS' occasional progressive bias, I sided with the slower ECM for the timing of the frontal passage, likely towards Wednesday night or early Thursday, with slightly warmer temperatures on Wednesday reaching the low 60s followed by rain, potentially heavy, overnight and possibly into Thursday. Temperatures will generally remain below average going into late next week as well with highs likely in the 50s behind the frontal passage. Stay tuned for more information on next week's outlook.