There is a lot of topics to discuss this morning and a lot of work to do.  I got a list like Santa Claus here with a lot of topics to cover!  Let’s see.  There’s Hurricane Paloma that is a major category 4 hurricane.  We are going to have to discuss why this hurricane strengthened so quickly and how it relates to the winter pattern!

Talking about patterns, we have another pattern change on the way and I’ll explain how today’s cold front is a trigger for cooler weather, but the real show is for later in the month.

Also, I’m going to look at some long range topics like the state of the stratosphere, latest ocean temperatures, and other important topics.  Busy morning coming up!  Plus, your local forecast.

The local forecast discussion is updated!

It sure was pretty windy last night, but today will be the complete opposite as the pressure gradient relaxes a bit.  However, more “fun” is on the way for Monday night and Tuesday morning and some people in the interior will even see some of those white flakes!

The winds have certainly picked up this afternoon as the pressure gradient between the slowly departing high pressure system and the low pressure over the Ohio Valley increases.  The good news is that the winds are from the south and southeast.  If you aren’t sure, then take a look at the winds blowing up RT 9 right now!  Seriously, when I was driving this morning; leaves, garbage, and those guys with those big advertising signs were all being pushed towards the north by a strong southerly wind!

So where is the rain?  

Well, the high pressure system to the northeast still has an impressive hold on the forecast area, which has blunted the lifting to the west to move into the forecast area.  The strong PVA that is supporting the rainfall over central PA will lift to the north and east, which will force the heavier rainfall over northern Pennsylvania, the Hudson Valley, and eventually into New England.  As for the rest of the forecast area, expect scattered showers through the evening with the main impact being the very windy conditions even as the winds veer back to the west and eventually the northwest.

I’ve been reviewing a lot of the site stats and one issues certainly comes across, my readers LOVE the technical forecast discussions.  In fact, besides the main page, the technical forecast discussion page the most visited page!  

So to help my readers out (BTW, THANK YOU FOR VISITING), I’m going to post the discussions on the main page.  I’m also going to be a bit more active in this nature, which I think will work out great as we head to what I think is going to be a very active and fun winter!  

So let’s get down to it!

I have some house work to do before writing the usual discussions, however I wanted to though out some quick thoughts this morning.

The rain is coming, but the worst of the rain is going to be focused to the north and west of the forecast area.  The best lifting dynamics are clearly setting up over the eastern Great Lakes like around my old college SUNY Oswego.  The forecast area can still expect rain today, but not nearly as heavy as what model guidance is suggesting from the most recent runs.  

As this storm lifts north today, the cold conditions will be rushing in to produce a VERY cold end of the week for October.  Hope you like frosted pumpkins!  

Finally, the trough axis for Tuesday looks a bit too far east to keep the low pressure that will develop close to the coast, which will limit the potential for precipitation.  However, I want to look at more guidance on this before I put the risk to bed.

10/24/08  7:58 AM

TODAY THROUGH SUNDAY:

A lot of moisture is surging out of the Gulf of Mexico this morning and through the Southeast as the strong upper low over the Plains begins to interact with the northern branch of the Polar Jet Stream.

Clouds will increase through today as moisture from the upper and mid levels begin to build.  Strong Canadian high pressure will exit the forecast area to the east, producing in combination with the developing low pressure system to the west, a strengthening southeasterly wind from the surface to 700 MB.  

As the upper low opens to a negatively tilted trough on Saturday morning, strong PVA along with impressive OMEGA values will move over the forecast area from late Saturday morning through the evening hours.  This strong lifting will lead to periods of heavy rainfall for the forecast area.  However, I still think the rainfall will move relatively quickly and I still think that rainfall amounts will generally remain below an inch over the forecast area.  

The low pressure system will lift through the central Hudson Valley on Saturday night and exit the region by Sunday morning.  The storm will still have a direct influence on the region, as a strong negative NAO blocking structure will develop, which will lead to an impressive cold air mass moving into the forecast area.

MONDAY THROUGH THURSDAY:

A strong cold front will follow on Monday with widely scattered showers, however the main influence of this cold front will be the crashing 850 MB and surface temperatures behind this front.  There remains some question as to the possibility of a coastal low impacting the forecast area.

The crashing heights and strengthening thermal gradient along with the impressive disturbance diving into the Mid Atlantic on Monday night all suggest a strong potential for cyclogenesis.  The strong blocking over the North Atlantic also would support a slowing of the disturbance and a rip environment for a deepening low pressure system.  However, the trough axis may be a bit too far to the east to produce precipitation over the forecast area.  Model guidance is having a difficult time handling this event at the current time.  However, given the atmospheric set up, I think the potential is very real and thus I included the rain/snow wording for Tuesday morning.

By Tuesday night, the surface low pressure system will lift into the Canadian Maritimes and bomb out, which will send a reenforcing shot of cold air into the forecast area through the end of the week.  

After Friday, the pattern will relax with a moderation of normal to possibly even slightly above normal temperatures for the start of November.  The pattern should begin to amplify towards the middle and end of November.  

The local forecast discussion is updated!

A very wet Saturday looks to be in the cards, and if you don’t believe that then check out the radar!  Meanwhile, a very cold end to the month is pretty much a lock, but there is still a question on whether a second storm will form for Tuesday morning.  Snow over the interior?  Yes, it is possible.

First, I just want to mention that I have updated the 2008/9 winter forecast with graphical explanations and illustrations for storm tracks.  

Model guidance now comes into strong support for a very chilly end of October as the NAO tanks along with the AO, which means some very cold 850 MB temperatures will be setting up over the forecast area.  There continues to be a high threat for a surprise coastal storm for Tuesday morning with an increasing likelihood for snowfall over parts of the interior.  I think the GFS is too fast in breaking down the pattern for next week and I prefer the slower depiction of the ECMWF for the last week of October.

Going into early November, I remain confident that the Polar jet stream will relax, allowing for the forecast are to moderate for at least the first 10 days over November.

10/23/08  7:54 AM

TODAY THROUGH SATURDAY:

A strong ridge is in place over the forecast area, which will continue to produce  clear skies and rather cool temperatures over the next 24 hours.  However, the upper level pattern remains volatile and ever changing as we progress through this month!  

A very strong and impressive upper low from the southern branch of the Polar Jet stream is slowly moving through the Plains with heavy rain and strong thunderstorms.  This upper level feature will spawn a low pressure system around the Gulf Coast that will eventually track towards the Ohio Valley by Saturday afternoon.  

The forecast area will remain on the warm side of this low pressure system, which means that surface to 700 MB winds will orient from the southeast beginning late Friday night or early Saturday morning.  Significant MAA from the Atlantic combined with moisture from the Gulf of Mexico will support high water content levels in the atmosphere.  As the upper low is captured by the northern branch of the jet stream on Saturday evening, the surface low will rapidly race towards New England and continue to intensify.  Heavy rain will race through the forecast area Saturday evening through early Sunday morning.  I’m starting to think this rainfall will end faster than model guidance is projecting based on the interactions I am seeing forecasted with this upper low and the northern branch.  So I’m staying below the rainfall amounts seen on the GFS for this period.  

This storm will bomb out over the Canadian Maritimes and produce a strong negative NAO blocking feature while the AO tanks as well.  The upper level pattern will then set up for an interesting disturbance for next week!

SUNDAY THROUGH WEDNESDAY:

A very interesting set up is unfolding for Monday evening and Tuesday, which should be an interesting test for this potential pattern in the winter!  

A strong cold front will race towards the coast on Monday with falling 850 MB temperatures along with crashing heights.  However, because of the blocking, the frontal boundary will stall off the coast on Monday afternoon, establishing an area of weakness between the coastal plain and the Gulf Stream.  Meanwhile, a disturbance will race down from the northern Plains towards the Southeast coast on Monday evening and produce strong divergence/difluence aloft, which will support a complete rising cuplet along the coastal plain.  As a result, a low pressure system will rapidly develop and deepen along the Mid Atlantic coast on Monday night through Tuesday, produce precipitation over the forecast area.  I think based on the 850 temperatures on the GFS, ECMWF, and ensemble guidance, that the GFS MOS may be too warm here so I went below the guidance.  The potential exists as the moisture interacts with the cold air moving into the region, that a mix of snow and rain or even a period of light snow will develop over the interior locations on Tuesday morning.  The areas most likely to see this will be over northeastern Pennsylvania, the Hudson Valley, and interior Connecticut.  

Obviously the forecast is important here, but what I’m keeping an eye on is whether the potential is realized for cyclogenesis and how the blocking features develop.  

As the storm bombs out over the Canadian Maritimes, the trough will remain in place through the end of October making for a chilling Halloween.  The pattern will relax some going into early November, as the NAO can’t stay negative forever.  However, a trough will still linger over the East going into November providing for near normal temperatures.