With a situated mean trough over the north east brought in by the heavy rain and a strong front on Friday and Saturday for most parts of the coverage area, we were lucky to see a sunny and cool "September" day for most of the area. Temperature departed for our areas are between 3 and 7 degrees below normal. This excessive drop in temperatures is not that uncommon in the area, but is rare enough to be mentioned.
The much cooler than average temperatures over the area is mostly due to the fact that we have a -AO hence a strong polar vortex to the north. This flip from a strong + AO to a negative AO in late July in conjunction to very good blocking with a -NAO has allowed a mean trough to build into the area and stay rather stagnant with multiple reloading phases thus far.
Here you can see the strong positive heights in northern Canada and into Greenland, mostly something you would see in a strong cool pattern in winter. But with position of the trough axis onver the area, the Hp with its clockwise flow will have winds out of the cooler Canadian 850s, and will force us to stay below average again for most parts. Most models have the trough reloading once again mid week bringing a front through increasing instability over the Wednesday to Thursday time period. this will allow a good inch to 2 inches of QPF to drop in most areas. But after that front moves through in the Friday, through Saturday time frame some model are hinting at the chance we could see one or 2 pop up 90 degree days, ambit with decent humidity. We will have warm 850s with a favorable SW flow due to the advancing trough and HP to the east and a slowly approaching front to the west. With the Southwest flow, the 850 temperatures will rise drastically improving the daytime heating effect. Here is the GFS for Friday clearly showing the rebuilding trough to the west with the above average temperatures ahead of it in the east.
The GEM agrees with this scenario.
Most models agree that the Warmest cities and areas will have the chance to hit 90, but most places will just stay 2-3 degrees above normal. yet again, Most models rebuild the trough into the east coast, but in the longer range telecommunications and the MJO forecast have put some light into the fact the Bermuda High might have a chance to retrograde back east as the heights in Canada and the very strong ridging in the southern US might weaken. Models are mostly split on rebuilding the heat, but it could be a likely scenario for the very end of august and into early September. A trough just to the west of the area with a South flow from the Bermuda high to the east may not be the greatest setup in the heat of hurricane season. But for now, enjoy the fall weather, and stay dry.
Ill be back mid week on a update on how the tropics might heat up quickly, how the pattern developing might put the east coast at risk, and maybe a quick thought on what we may be in for next winter...or i might wait for that. Lol.
Have a great week.
Ryan Remondelli
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