If you're not enjoying life as much as I am, it's not my fault!
Rank: F5 Superstorm
Blue Mtn, N of Hbg - Elev 1000'
Joined: 12-February 10
Profile Views: 10,174*
Last Seen: Today, 04:18 AM
Posting in topic: Dec 8-9 MidAtl/NE Storm OBS
Local Time: Dec 8 2013, 04:28 AM
6,654 posts (5 per day)
* Profile views updated each hour
19 Oct 2013
0z Euro Op
0z GFS Op
When two Op are not in total agreement - always good to go to the ensembles. I don't have access to the Euro Means but the GEFS individual memebers are here.
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1253 AM EDT SAT OCT 19 2013
VALID 12Z TUE OCT 22 2013 - 12Z SAT OCT 26 2013
...OVERVIEW AND PREFERENCES...
AMPLIFIED PATTERN FROM THE PACIFIC ACROSS NORTH AMERICA SHOULD
HOLD RELATIVELY IN PLACE... WITH RIDGING OVER WESTERN CANADA AND
TROUGHING THROUGH THE CENTRAL/EASTERN CONUS. A CUTOFF LOW BETWEEN
HAWAII AND ALASKA HAS MORE SUPPORT TO UNDERCUT THE RIDGE IN THE NW
AND MAY PUSH INTO CA LATE NEXT WEEK. THE MODEL/ENSEMBLES HAVE
SHOWN GOOD SYNOPTIC AGREEMENT BUT REMAIN IN A STATE OF FLUX WITH
THE DETAILS. THE 12Z/18Z GFS RUNS FALL OUTSIDE THE BETTER
CLUSTERING OF THE 12Z ECMWF WITH THE GEFS/ECENS MEANS... AND EVEN
THE 12Z UKMET/CANADIAN ARE NOT TOO FAR OFF. IN THE WEST... THE GFS
KEEPS THE UPPER LOW WELL OFFSHORE CA LATER IN THE WEEK AND IN THE
EAST IT LIES WELL EAST OF THE ENSEMBLE CLUSTERING JUST OFF NEW
ENGLAND THU/D5. THE 12Z ECMWF MAY BE TOO DEEP WITH THE WESTERN
UPPER LOW AND TOO CLOSE TO THE COAST IN THE NORTHEAST... BUT
OTHERWISE SEEMS REASONABLE. HOWEVER... GIVEN THE CHANGES SEEN FROM
RUN TO RUN... RELIED MORE ON THE ECENS MEAN AND SOMEWHAT ON THE
GEFS MEAN ESPECIALLY BY DAYS 6-7.
Further out in time requires a look in from further out in space (Paul Knight - PSU) In other words, look "upstream"
The biggest difference between the big 2 Op runs is that the GFS keeps the trough on a progressive (or positive) orientation too long while the Euro (rightfully so IMHO given the flow aloft) swings the trough to Neutral or slightly Negative just at the "right" time. I say rightfully so because of the "draw" of the Canadian cyclones shown in both models - I would think that would "pull the string" on any developing SLP rounding the base of the trough (imagine pulling on a dog's collar when it tries to run after a cat - sorry animal lovers but that's the best analogy I can think of this early).
The thickness and 850mb lines suggest this is an "interior" special (from the Apps and north and west for any wintry precip to speak of). Euro really turns it into a "stem winder" as it comes up the coast so by the time it hits Atl Canada/Maritimes, it is showing as what looks like a sub 990mb. At Hr 168 it is well beyond the region but at a raging sub 960?
As always we will have to watch this unfold. If the "pick the middle one" idea works, then the colder air could shift east and get some "nearer to but probably not at" the coast seeing some "white rain" mixing in.
10 Oct 2013
Trying to get in "board" shape for the upcoming winter season (and to heed our buddy DH-FF) I decided to go ahead and open an Obsx thread.
So first, a few pictures.
With all apologies for early morning "art work" - we see some very nice low topped convection just now at the Atl Coast of NJ/DE (and to a lesser extent, VA/MD). The highest tops running ~12K' with only one area of rotation - but it too is weak.
The H7-H8.5 moisture transport is pulling some serious PWAT along and just to the south of the largest pressure gradient (as is expected). Current PWAT according to SPC Meso Analysis is well over 1.5 and in the northern periphery somewhere in the area of 2.0"
Pressure falls are greatest at or near the area I have indicated. As you would expect the height falls are quite meager (storm cannot bomb out because the upper winds are not ventilating it). This region IMHO is under the gun the most for heavy to excessive rainfall potential. The region north of the systems present location is not seeing ANY height rises - indicating that the HP is not ready to push back in any meaningful way. I also tried to show the area of the best gradient and exposure to wind potential.
And speaking of upper air - the H3 flow is trying to squeeze off - making it the last level of heights to do so. The lower levels remain stacked just off shore, but H5 and H3 are pinched off well inland - not allowing for any movement any time soon.
Now lets switch to a bigger picture view. Water vapor imagery
Note the very dry air to the systems immediate south. That could be a big relief to areas of the coastal Carolinas - but will likely do us no good in the way of abating the rain. Without decent voriticity values, the system would not be able to entrain much, if any, of that dry air. The Atlantic feed will all but assure we stay wet-moist-wet for the next 60+ Hrs.
The sounding (SKEWT) shown next is a random location within the greater area "under the gun". We see deep moisture from H7 down but upper air drying from H5 and up.
Note also the 925mb wind flow - near 40 from the east.
And, finally some pro thoughts from WPC
Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EDT Thu Oct 10 2013
Valid 12Z Thu Oct 10 2013 - 12Z Sat Oct 12 2013
--Rainy and windy for the Mid-Atlantic and Northeast--
--Thunderstorms with rain and snow across the Inter-Mountain West--
A nor'easter, which includes Post-tropical cyclone Karen's surface
circulation/area of low pressure, will bring widespread showers and
thunderstorms with winds to gale force along and just offshore the coast
from eastern North Carolina to southern New England. This moisture-laden
cyclone should cause a few inches of rainfall to unload upon the northern
Mid-Atlantic states over the next couple days, with New Jersey slated to
get the lion's share of the rainfall. Overcast conditions are likely to
continue through Saturday due to the system's slow movement and an
invading backdoor front bringing in drier air as it moves through the
Mid-Atlantic states Saturday.
So that's all for the first post from me - I have no rain ATTM, not even really "feeling" like rain either. But it is on the doorstep and by the time I head off to work, expect to be using "misting" wiper mode.
Have a good one folks.
29 Aug 2013
I was just peeping the 12z GFS 4 panels and noticed that the H5 vorticity, the H7 humidity, at Hr60 and beyond match up extremely well over C PA and some areas of NOVA. The threat for NE looks to be a bit earlier (maybe 8/31 in the p.m. hrs) which seems to quash development to a certain extent but there are remnant weak spins matching the 700mb moisture.
There does not appear to be a ton of shear and what there is seems more surface based. So convective activity may be kept to some good light shows and much thunder, maybe some local FF (as the SKEW T suggests very effective transport of the moisture down through the column).
(C PA for illustrative purposes)
SPC downplays the potential - not even mentioning our area in the discussion while still "coloring" us as "See Text".
22 Aug 2013
I decided to pull the trigger on a thread for next week's heat. The DGEX temp profiles suggest that the lower Mid Atl starts (as expected) as VA/MD/DE region appear to crack 90's as early as 8/28 with the rest of the Mid Atl and southern parts of the Northeast having to wait until another day or so.
The system that delays this from being a heat wave. LP off the Carolina Coast near the 8/26 tm pd. is now showing on both the GFS and EURO as being a bit transitory as well as a bit more off the coast as opposed to directly at. This would allow the H5 ridge of heat to translate east into the area and in earnest near the 8/29-30 time period for much of the region with the possible exception of northern New England.
After 9/1 it does not look like it's "heat over" days. As there does not appear to be an all out retreat of the H5 ridge and it's influence will still be felt in the East - just not so strongly as end of August is looking.
DGEX for 8/28 (focus on surface temps)
GFS for 9/1 (focus on 850 temps)
Euro for 9/1
30 May 2013
Start off with SPC thoughts:
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 300836
SPC AC 300836
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0336 AM CDT THU MAY 30 2013
VALID 021200Z - 071200Z
MEDIUM RANGE MODEL GUIDANCE SHOWS A MID-LEVEL SPEED MAX MOVING
ACROSS THE NERN U.S. IN ASSOCIATION WITH A MID-LEVEL LOW/TROUGH OVER
THE GREAT LAKES/ONTARIO ON SUNDAY /DAY 4/. A MOIST/UNSTABLE AIRMASS
WILL ADVECT INTO THE REGION AND SUPPORT AN ENHANCED CORRIDOR FOR
STRONG TO SEVERE STORMS WITHIN A LARGELY UNIDIRECTIONAL SWLY WIND
PROFILE SUPPORTIVE OF STORM ORGANIZATION.
Twister data shows CAPE of over 2000 j/kg and Lift of nearly -8 but little shear for most of the region near 40N in PA on the 2nd. On the third, the shear increases to a modest to robust 40-50 region wide but only meager CAPE and that is focused on the 95 corridor.
One thing for sure - 850 moisture is really strong and easily will ride the southwest flow into the region. Flash flooding may have to be watched as a mostly linear line up of training storms and heavy precip conspire to make things "interesting"
4 Dec 2013 - 7:41
30 Nov 2013 - 12:11
20 Nov 2013 - 5:50
20 Sep 2013 - 14:07
12 Sep 2013 - 4:32
Other users have left no comments for Undertakerson.
There are no friends to display.
|Lo-Fi Version||Time is now: 8th December 2013 - 04:28 AM|