Possible MCS Event for the 28-29th

Sorry for the lack of posts,
Weather has been lacking in excitement.
Anyay, it looks as if we could could be in for a possible MCS event for the 28-29th. MCS stands for Mesoscale Convective System, and is basically a large concentrated squall line that travels extended distances. And it looks as if we have a good set up for one to form. The GFS and the EURO are at much different solutions right now. The GFS want this MCS event to be a more mid Atlantic event, actually missing us with the precip to the south, while the EURO Is more of a hit for the area. The Difference in the solutions is really at the 500mb level. BY that time it looks as if their will be a +EPO, and a Negative PNA. Meaning that their will be a ridge in the pacific telleconnecting to a trough on the west coast, connecting to a ridge in the central part of the country, and a trough in the east. Thats how telleconnections work, its all physical reactions.

But at the 500mb the EURO and GFS are quite different were they want to set up the ridging in the middle of the country.

The GFS want to develop a much more_PNA thus a sharper trough into the west coast allowing the center of the ridge to be further west. With the sharper trough in the west, the reaction in the east coast to the farther west ridge is a much sharper and south trough in the east. 

This allows for the energy and precipitation associated with the ULL to dive much further south missing the area.

Meanwhile the EURO and its better physics drive, is showing a less amplified -PNA trough in the west coast, allowing a more east based center of the ridging. The only allows for a weaker and more east (offshore, more zonal for our area) based trough , keeping the ULL more to the north, thus the MCS convection to the north also hitting the area.

This more northern track puts us in the line of fire

The GEM also agrees with the EURO in terms of set up. But has a more amplified west based trough in the east allowing for the MCS convection to come right through the mid Atlantic

The GEM is the moderate here in the situation.

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Im betting on a track between the Euro and the GEM and their more advanced physics drives with this one. But we will see in the coming days how the models advance with the pattern.

Have a good one. 

Cooler weather, tropics heating up

Hi all,
With the trough nicely situated in the east for the next couple days, a high pressure sitting to our west, and cool 850s above with clear skies, i think we have a chance for some record lows tonight. Models have most people on the coastal plain bottoming out in the low 60s, due to marine layer influence, but people 50-60 miles inland that have a more Northerly flow from the HP to the west, will see temperatures reaching into the 50s, and maybe a outside chance for a high 40 degree reading, especially in the tallest mountainous areas.
A look into the tropics sees invest 92-L in the Caribbean, and invest 93 in the Atlantic. Both are given a high probability by the NHC in formation.
 I believe invest 92-l is a greater threat to the immediate US coast at this time, given most ensemble models forecasting it to be picked up by a approaching frontal boundary to the north and directed into the Southern US coast. Intensity models are varying greatly with 92-L given the exact formation and position of the stacked LLC, and MLC is not fully observed and or known yet, giving forecast models a hard time forecasting how much interaction with the Yucatan Peninsula and how much time over the warm GOM SST it will have. If 92-l takes a more slower and westward track with more interaction with the Yucatan, it could be at a greater risk with increased wind shear and of course land interaction disrupting the circulations developmental ability and sustainment. But if it takes a more  expedited and easterly track, it has a greater chance to develop over the warm SST and a more favorable environment.
Invest 93 is a little less exciting. Given the foretasted movement to the NW, it looks as if 93 will eventually develop, but will likely be held to lower strength and intensity over the next couple days due to cooler SST, and the increased presence of the Saharan Dry air still embedded in the Atlantic.
I guess it is a race to the next name storm....
Have a great day!
Ryan Remondelli

Heavy Rain on Way tonight. Possible Severe Weather too.

Hello all,
Quick update. Looks like we could be in for a possible severe weather event tonight. Even if severe weather does not effect your area,  you will see very heavy rain.
With the convection approaching from the west of the area, it has become clear that their will be 35+ km of shear available for the super structure of the thunderstorms in some parts of the area. This will allow the thunderstorms to maintain their strength as they move into our areas. Severe weather potential mostly likely further east in the coverage area as the foretasted shear is greatest their. Without high instability, and thermodynamics in the west coverage area, severe potential is less likely and some what more limited. But in the eastern coverage areas (Eastern NY west, Central PA west) with higher thermodynamics and much higher bulk Shear Values, the chance is greater. Expect between .75 and 2 inches of rain with heavier in isolated spots with trailing convection lines. Rain should move in tonight and last into tomorrow morning before we cool down for the reaming week. Their is a coastal storm chance during the week, as models have hinted that a low Pressure will form in the GOM and ride the ridge axis and effect our area. That system needs to be ironed out later.
Stay safe tonight and tomorrow.
Ryan Remondelli

A quick update,
Rain continues tonight and into Friday as instability hangs around from the approachng trough. After a quick chance for mid to upper 80s this weekend with warmer 850's and a SW flow, most models show a reloaded trough moving back east that could be stronger and more vertically oriented, or more zonal than this past one, either way keeping us below average for most of next week. As i mentioned, i  think the question is how  below average we will get. Models agree on moving in a trough, but their is a discrepancy on how vertically oriented and strong the trough itself will get. taking a look at the GFS and GEM discrepancy at the 500mb heights. Both show a strong ULL over Canada between 136 and 150 hours,

The GEM has a 594 DM high popping a strong + PNA ridge in the west. You can also notice the HP center is further west itself. This allows the Upper Level Vort over Canada to react and form a sharper and stronger vort with tighter pressure gradients over the Eastern US and Build a strong 1023mb high on the back side of the trough

 

With the tight trough over the Eastern US with a strong Vort Max over Canada it allows even cooler air to filter in behind the departing ULL bringing much below average 850's and in turn temperatures.

 

The GFS on the other hand has a much weaker Hp is the SW that is displaced further east due to the GFS's accelerated movement of the ULL. With out the HP being further west and in a more stronger and dominating position, it is unable to form a more vertically oriented Positive ridge in the west, therefore not allowing the ULL to dive further south and enhance the trough, making the pattern in the Eastern US more zonal than the GEM.

 

At 150 hours you can easy see the difference between the GFS and GEM, the GFS has the ULL much father to the east than the GEM, and a almost complete zonal pattern with little vertical tilt to the Jet stream. this allows more seasonable temperatures to stay in the area with a west wind rather than a cool NW or N wind  and allowing the bulk of the cooler weather to the west.

 

Their has been a trend to a weaker trough in the east in this time period over the last day or two. If this trend continues we will not see much below average temps, but if the global guidance holds suite we could be in for a even more pronounced cool down. We will see how models trened the next couple days.

Cooler Start to the week, then rain for the area.

Hello all,
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