Foot's Forecast | Weather Intelligence

THE GROUNDHOG STORM OF 2009?

SYNOPSIS: THU JAN 29 - 7:15 AM. Upper level and climate indicators are pointing towards a very significant to near-historic event for the East Coast in the Monday - Wednesday period next week. A current view of NOAA's GFS (Global Forecast System) projection for 8PM Monday night shows a deepening surface low moving generally north to northeast just along the coast. An interesting trend that's developed in the most recent set of runs on this particular model clearly shows a surface high of increasing strength, and a slight eastward drift in the low track. There is still considerable time in front of this storm and multiple changes are in the offing. You will know for sure that serious concern is building if your local NWS office posts a Hazardous Weather Outlook Friday or Saturday.

Note to readers: I am away all day at training so no updates until 8PM at the earliest. You are welcome to post your questions in the comments section below (just not during school time of course!). Schools will be on time Friday regardless of possible melting and refreezing tonight. Let's get this marking period started, you all need to put as many days under your belt as possible... the weather pattern going forward the next two weeks will be challenging.

This system, first named here as the "Groundhog Storm," was done simply because Punxsutawney Phil's big day is Monday 2/2. By then, according to HPC and others, we might have a "full-latitude trough" across the Eastern US, which is an extremely huge deal because it only happens once every couple winters. When the atmospheric ingredients are right, it can spawn a storm for the record books, such as February 1978, The March 1993 Superstorm, or the Blizzard of January 1996 with little prior warning. It's unoffically called "Bombogenesis" and occurs when a historic, crippling storm seems to explode out of nowhere within 24-36 hours. The NWS Climate Prediction Center, as well as NWS forecast offices, and local emergency management are closely tracking this potential because they know it can happen so quickly and allow little time for preparation.

That said, now look at what the HPC said on Wed 1/28, (current discussion here): Some text removed for clarity and space.

"JUST AFTER GROUNDHOG DAY...THE VIGOROUS 00Z/28 GFS COASTAL CYCLOGNESIS LATE MON INTO WED IS POSSIBLE AND CANNOT BE RULED OUT....THOUGH WE ARE NOT PRESENTLY BOMBING OUT THIS SYSTEM. A DEEP UPPER CYCLONE COULD BRIEFLY CLOSE OFF AS FAR SOUTH AS TENNESSEE OR NORTH CAROLINA BEFORE LIFTING NORTHWARD. A DEEPENING SURFACE CYCLONE COULD MOVE NORTH TO NORTHEAST FROM THE GULF OF MEXICO UP THE PIEDMONT...EASTERN SEABOARD...OR THROUGH WESTERN ATLANTIC WITH USUAL WINTER WEATHER CONSEQUENCES. WE HAVE NOT SEEN THIS TYPE OF CYCLONE TRACK TOO OFTEN THE PAST COUPLE WINTERS."

HPC most current ideas as of 3:10 AM Thursday are: "IN THE EAST...THE MODELS CONTINUE TO TREND DEEPER WITH A CYCLONE EXPECTED TO TRACK NORTH-NORTHEAST FROM THE GULF OF MEXICO INTOEASTERN CANADA...SO THE FORECASTED PRESSURES FOLLOW SUIT. THE COMPROMISE CHOSEN TAKES THE SYSTEM UP THE FALL LINE...A SPRING-LIKE TRACK. THE 12Z ENSEMBLE MEMBERS HAVE TIGHTENED UP AND SHIFTEDLEFT SINCE THIS TIME YESTERDAY AND AGREE A TRACK UP INTERSTATE 95. THEIR CLUSTERING INCREASES THE CONFIDENCE IN THEFORECAST TO ONE WHICH IS ABOVE AVERAGE. IF THIS FORECAST VERIFIES...THE THREAT OF HEAVY SNOWFALL WOULD BE ANTICIPATEDACROSS THE CENTRAL AND NORTHERN APPALACHIANS AS WELL AS THE EASTERN GREAT LAKES."

Now consider this section from the CPC's bi-weekly hazards assessment report:

"LOW PRESSURE WILL MOVE NORTHEASTWARD FROM THE GULF OF MEXICO TO ALONG OR JUST INLAND OF THE EAST COAST. THIS SYSTEM HAS THE POTENTIAL TO BE A HIGH IMPACT EVENT FOR THE EASTERN CONUS BUT IT IS TOO EARLY TO DEPICT SPECIFIC HAZARDS ASSOCIATED WITH IT. (then, later in text:) THE LOW PRESSURE SYSTEM FORECAST TO MOVE UP THE EAST COAST MAY BRING SIGNIFICANT PRECIPITATION TO PARTS OT THE EAST."

Finally, here's what the Sterling, VA NWS office latest thinking with this storm:

"OPERATIONAL GFS AND ECMWF ALONG CONTINUE TO COME MORE IN LINE IN PROJECTING A DEEP NEGATIVELY TITLED 500 MB AND ASSOCIATED CLOSED LOW SPAWNING A COASTAL LOW OFF THE SOUTHEAST CONUS THAT WILL MOVE UP THE COAST EARLY NEXT WEEK. HAVE UPPED POPS TO HIGH CHANCE...AND THE SYSTEM WILL BE CLOSELY WATCHED."

Please note I am not implying we're headed for a blizzard, I'm referencing my sources in alerting you to the likelihood of a high impact event next week. As Andy of York County in the comments has pointed out, a lot could go wrong in the development of this storm, so it is too early to say we're in for big snow. It'll be a very big something, just not sure exactly what yet. To prepare the data on tracking this event, the indicators to be closely researched and monitored for signs of development include:

- Will the North Atlantic Oscillation trend negative next week as is expected?

- Can the Pacific-North American Index trend positive, thus enhancing an East Coast trough?

- Will Pacific moisture associated with the Madden-Julian Oscillation Phase 1 be involved?

- Are computer models correctly depicting the strength and location of High pressure cells?

- Are computer models ALSO correctly initializing how a negative NAO could affect the flow?

There is much to research on this storm, but I caution against making bold proclamations too early. Once the upper level energy that will be responsible for spawning this is over US terrority, accurate radiosonde (weather balloon) data can be fed into the computers, and THEN at around Day 5, we will start to see where this first possible BIG KAHUNA of the season is going to do. I can tell you this, it reminds me very much of something I once told my Earth Science class way back on February 14, 2003: "We're either going to have 3 inches of wind-swept rain and thunderstorms, or 3 inches will be the liquid equivalent of something else."

POST STORM REPORT: I will be adding details in this section.

ABOUT THIS SITE AND THE AUTHOR: Since some of you have recently learned of the site, I figured it would be helpful if you knew what this is all about, and some background on who is the guy behind it. That discussion will be added here.