“Hi Steve. Speaking of storms and weather patterns what do you think about the low off the east coat. Looked ominous on the surface charts and even more so on the 500 mb charts. Some weather sites are calling it a low pressure “bomb”. I have read your Mariners Weather Handbook a few times through and this system seemed like a good learning opportunity.”
Thanks for the heads up, Mike:
For anyone interested in weather, this is what gets the adrenalin flowing at the Ocean Prediction Center. Right now this is just a hurricane strength storm forecast, bad enough if you are caught in it,
but it has the potential to create enormous waves because of its size and the possibility of a dynamic fetch event (see Mariner’s Weather Handbook for more on this little known phenomenon).
The 500mb chart above gives a hint of what may come. You have high pressure over Greenland (only part of which is shown) high pressure to the south, and an intense low squashed between them.
The 24 hour surface wind and wave report above shows the start of the action.
And then the 48 hour forecast. If you are caught, staying out of the south east quadrant is critical to the best chance of having a positive outcome. Note the speed at which this system is forecast to travel. When the storm systems travel at the same speed as waves propagate, huge waves are created. It doesn’t happen often – and probably won’t here, but if it does, with this combination of features, we could be hearing about 65 to occasional 100 footers (20/30 meters).
You can see the complete run of faxes here.
Below is the duty forecaster’s commentary on what he sees in the models, a form of dialog between forecasters, that can help you spot problems ahead of the officially released forecasts.
AGNT40 KWNM 300114 MIMATN MARINE WEATHER DISCUSSION NWS OCEAN PREDICTION CENTER WASHINGTON DC 914 PM EDT SAT 29 OCT 2011 .FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT .WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N. ENHANCED SATELLITE IMGERY OVER THE WRN ATLC INDICATING STG JET SEGMENT WITH EMBEDDED SHRTWV TROF MOVING OFF THE CST AND DRIVING NE ACROSS THE OFSHR WTRS. ALSO LATEST MDLS CONTINUE TO INDICATE STG INTSFYG LOW PRES MOVING NE OVER THE NRN MID ATLC INTO NEW ENG WTRS. ADDITIONALLY MDLS SHOWING GOOD INTIALIZATON WITH LATEST RU2 OVER THE NRN MID ATLC INTO NEW ENG SHOWING STG AGREEMENT WITH EHANCD CONVECTION AND THE ASSOCD SATELLITE IMAGERY. . AT THE SFC...DVLPG LOW 180 NM E NE OF CAPE MAY AT 996 MB AT 00Z WITH A MATURING FNTL BNDRY. THIS LOW ABOUT 1 TO 2 MB LOWER THAN THE LATEST GFS AND ECMWF AND IN LINE WITH THE LATEST UKMET AND 4 KM NAM MDLS. THIS LATEST DVLPMNT OF THE LOW REMAINS IN LINE WITH THE TRENDS OF THE MDLS...THEREFORE STILL GOING WITH STG INTENSIFICATION TRHOUGH THE NEXT 24 HOURS...A WILL CONTINUE TO FOLLOW THE TENDS NOTED IN PREVIOUS DISCUSSION. AS FOR SEAS...HAD A RPT SE OF LONG ISLAND TO 29 FT...BUT OTHER OBS NEAR BY IN THE UPPER TEENS...WILL GO FOR ARND 20 FT NEAR THIS LOCATION...OTRW CONCERN THAT WAVE MDLS ABOUT 3 TO 5 FT LOW IN PLACES OVER THE WRN ATLC. PREVIOUS DISCUSSION........................................... GLOBAL MDLS APPR TO HAVE GOOD INITIALIZATION ON INTSFYG CSTL STORM APCHG BALT CNYN AND RMN TIGHTLY CLUSTERED AS LOW PASSES THRU SERN NT1 WTRS TONIGHT AND E OF WTRS SUN MRNG. 12Z CMC GLOBAL AND ESPCLY NOGAPS RMN SOMEWHAT WEAKER AND FASTER BUT PREFER PSN NR HAGUE LN NEAR 980 MB GIVEN STRONG DYNAMICS OF ASCD JET STRM SPRT...WITH 12Z NAM4 SHOWING UPR 970S AT THAT TIME AND GFS ALMOST AS DEEP. GFS 30M WNDS PEAK AT 65 KT GLF OF MAINE EARLY SUN AND GENLY SPRTS CURRENT FCST BUT 4KM NAM SHOWS BL WNDS 70 KT GETTING INTO NW GEORGES BANK IN LN WITH EARLIER RUN SHOWING 10M WNDS 64 KT. PLAN TO EXPAND HURCN FRC WND WRNG INTO THAT AREA. OTRW WILL PLAN ON NO SGFNT CHANGES OTHER THAN FAR SRN GALE WRNG FOR TONIGHT THRU MON AS STORM PASSES NE OF AREA FOLLOWED BY HIGH PRES. MON NIGHT THRU WED MDLS DVLP A WAVE FM S OF AREA AND MOVE IT NE...SKIRTING OUTER NT2 WTRS BEFORE PASSING WELLS OF NFLD LATER WED. ECMWF HAS BEEN MOST CONSISTENT OF MDLS IN HNDLG THIS LOW AND PLAN TO GO WITH IT EXCP SOME BLENDING WITH STRONGER UKMET TUE AS LOW PASSES JUST E OF CENTRAL NT2 WTRS. DUE TO COUNTER FLOW TO GLF STRM AND NE FLOW 10 M WNDS MAY BE TOO LOW. PLAN TO UPGRADE SE BALT CNYN TO HAGUE LN TO STORM TUE INTO WED WITH LOW TO MOD CONFDC BUT OTRW CONT WITH PREVIOUSLY FCST GALE WRNGS. WILL GO WITH MDL CONSENSUS ENDING GALES LATER WED AND DMSH WNDS THU AS HIGH PRES RDG MOVS OVR WTRS. SEAS ARE STARTING OUT 2 TO 5 FT HIGHER THAN MWW3 NRN NT2 INTO SRN NT1 WTRS IN INCRG E TO NE FLOW. AGREE WITH PREVIOUS THINKING THAT MDL COULD BE AT LEAST 2-4 FT LOW ARND THE DPNG SYSTEM ESPCLY N OF HAT CNYN THRU MON. FOR THE DVLPG WAVE OFF SE CST SINCE ECMWF/UKMET PREFERRED WILL USE ECMWF WAVE MDL EXCP INCRS VALUES 20 PCT IN NRN AND CENTRAL NT2 WTRS IN CAA AND COUNTER FLOW TO GLF STRM. EXTRATROPICAL STORM SURGE GUIDANCE...LATEST RUN OF THE ETSS MDL STILL INDICATING SURGE ALONG THE NJ COAST NE TO LONG ISLAND AND IN LINE WITH THE TRENDS OF THE GFS. VALUES PEAK UP TO 2 FT NJ CST AND 2 TO 3 FT L.I. SOUND THIS EVENING AND 1 TO 2 FT CAPE COD E CST NWD TO SRN MAINE LATER TONIGHT AND EARLY SUN LOOK RSNBL...WITH VALUES GOING NEGATIVE TO SML POSITIVE IN N TO NW FLOW BHND STORM LATER SUN. .WARNINGS/FORECAST CONFIDENCE...PRELIMINARY. ANY CHANGES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .NT1 NEW ENGLAND WATERS .GULF OF MAINE...STORM OVRNGT...MDT TO HI CONFDC. HURCN FORCE WINDS SUN...MDT CONFDC. .GEORGES BANK...STORM OVRNGT...HI CNFDC. HURCN FORCE SUN...LOW TO MOD CONFDC. .S OF NEW ENGLAND...STORM OVRNGT INTO SUN...MDT TO HI CONFDC. .NT2 MID ATLC WATERS .HUDSON TO BALT CNYN...STORM OVRNGT...MDT CNFDC. .BALT CNYN TO HAGUE LINE...STORM OVRNGT INTO SUN...MDT TO HI CONFDC. STORM TUE INTO WED...LOW TO MOD CONFDC. .BALT CNYN TO HATTERAS CNYN...GALE OVRNGT...MDT TO HI CONFDC. GALE TUE INTO WED...MDT CONFDC. .HATTERAS CNYN TO CAPE FEAR...GALE OVRNT...MDT CONFDC. GALE TUE INTO WED...MDT CONFDC. .CAPE FEAR TO 31N...GALE OVRNGT...LOW TO MOD CONFDC. .FORECASTER MCRANDAL/BANCROFT. OCEAN FORECAST BRANCH.
Posted by Steve Dashew (October 30, 2011)
October 30th, 2011 at 10:06 am
Steve. Thanks for posting the acticle. I am not sure if you can pull the faxes up from yesterday, but if you can they are interesting as well. Not nearly as exciting as whats happening now but I think they would have served as a good early warning. When the low was just to the south of Norfolk the upper air charts showed a trough over the great lakes that was fairly deep and it’s axis went pretty far south. Upper level winds indicated 70 kts; this was on the 00Z charts. On the next set the surface low had moved north a bit, maybe abeam the eastern shore of Maryland so not to far i think but the trough had moved a lot quicker with it’s axis approaching the surface low and the upper level winds still in the 70 kt range. That was the 12hr and still no low noted on the upper air charts, it seemed like it was coming though. Then on the 24 and 48 hr charts they noted the low on upper air analysis and it was just to north of the surface low with even stronger upper level winds and this appeared to happen when the trough met the surface low. All this before hurricane force winds were noted.
Hope that description is of value. Maybe you can check out the charts from yesterday. My thoughts are that if you happened to be in the North Atlantic yesterday you might have been able to see this coming a day in advance and better your chances of not seeing severe weather
Thanks again
Mike
October 30th, 2011 at 10:35 am
Mike:
I don’t have yesterday’s but if you can send them to me we’ll discuss the warning signs. The key is the 500mb shape and speeds, and the telltales are typically first observed when a trough begins to form over the great lakes.
October 31st, 2011 at 8:11 pm
Steve: I sent NOAA an email to get the older charts and was successful. I will be sending you copies of the charts from the 29th tonight in addition to NOAA’s reply as it contains the links to the web pages that display archived charts.
Thanks again for the interest.
Mike
October 31st, 2011 at 8:23 pm
Sounds great, Mike:
Also, the previous day would be of interest.
November 8th, 2011 at 6:47 pm
In London, the systems for weeks have passed N of us, and the weather has been very mild, in contrast to recent years when this time of year has experienced the strongest winds. In contrast, in September the North Sea was the target.