Friday, February 27, 2009

Storm Enters NYS, Brings Warmth, Rain, Possible Flooding

As forecasted, the low pressure system will be moving through today, providing NYS with seasonably warm temperatures and rain. Some parts of western and central NY, along with some of the higher elevations, could receive a little snow at the tail end of the precipitation. A few rumbles of thunder may also be heard. Flooding remains a concern in rivers and streams, with the combined effects of melting snow and rainfall, especially in the Adirondacks and Catskills. Here is the flood watch issued today for these parts:

THE NATIONAL WEATHER SERVICE IN ALBANY HAS ISSUED A

* FLOOD WATCH FOR A PORTION OF EAST CENTRAL NEW YORK...INCLUDING
THE FOLLOWING AREAS...EASTERN ALBANY...EASTERN GREENE...
EASTERN SCHENECTADY...EASTERN ULSTER...HAMILTON...MONTGOMERY...
NORTHERN FULTON...NORTHERN HERKIMER...SCHOHARIE...SOUTHERN
FULTON...SOUTHERN HERKIMER...SOUTHERN SARATOGA...WESTERN
ALBANY...WESTERN GREENE...WESTERN SCHENECTADY AND WESTERN
ULSTER.

* THROUGH LATE TONIGHT

* MILD TEMPERATURES TODAY WITH HIGHS IN THE UPPER 40S TO MID 50S
WILL RESULT IN MELTING SNOW ACROSS THE WATCH AREA. IN
ADDITION...A THIRD OF AN INCH TO THREE QUARTERS OF AN INCH OF
RAIN IS EXPECTED TODAY INTO EARLY THIS EVENING AHEAD OF A COLD
FRONT WHICH WILL BRING COLDER TEMPERATURES BACK TO THE REGION
LATER TONIGHT. THE COMBINATION OF RAINFALL AND SNOW MELT MAYBE
ENOUGH TO DISLODGE SOME OF THE ICE ON RIVERS AND STREAMS. THE
ICE CHUNKS WOULD THEN FLOAT DOWNSTREAM AND MAY FORM ICE JAMS
WHERE THE RIVERS TRANSPORT CAPACITY IS EXCEEDED. FAVORABLE
LOCATIONS FOR ICE JAMS INCLUDE...OBSTRUCTIONS IN THE CHANNEL
SUCH AS ISLANDS...LOCKS AND BRIDGE PIERS...CHANGES IN THE
CHANNEL SUCH AS BENDS...GORGES AND AREAS WHERE THE CHANNEL
NARROWS...AREAS WHERE THERE IS A CHANGE IN CHANNEL DEPTH...DEEP
WATER TO SHALLOW WATER...AND MERGERS OF RIVER CHANNELS.

* ICE JAMS CAN OCCUR SUDDENLY AND ARE HIGHLY UNSTABLE. WATER CAN
BACKUP QUICKLY BEHIND AN ICE JAM AND FLOOD AN AREA IN A MATTER
OF MINUTES. IN ADDITION...IF AN ICE JAM BREAKS A SUDDEN RELEASE
OF WATER CAN FLOOD AREAS DOWNSTREAM.

Also, looking at Buffalo's sounding from this morning, it looks like there is also the possibility of strong, gusty winds occurring in western and central NY along the cold front as it passes through. A band of moderate rain will likely accompany the wind.

The second storm, forecasted for the end of the weekend, appears to be tracking further and further off the coast. This means that most of NYS will not be getting any precipitation from it. Portions of southeastern NY might receive a light rain/snow mix Sunday morning as the system moves off the coast.

Cooler temperatures will take a hold in NYS after the passage of the second storm, as high pressure moves into the region. This high might get temporarily broken down in the middle of next week as a clipper system moves across the state, bringing light precipitation at best. The high will then rebuild after the clipper passes through.

Monday, February 23, 2009

Rain/Snow Storm Friday, With Storm Possibilities Sunday

The models are agreeing fairly well on a mixed rain and snow event for Friday. Most of the state will receive rain, with periods of freezing rain and sleet. As the cold moves in behind the low, snow will also be present for areas of western and northern NY and at higher elevations:



Some areas in NYS will be susceptible to flooding as this storm moves through, as the rainfall and seasonably warm temps will eat away at the snow pack. Icy sidewalks and pavements will also be a concern during the overnight hours, as the temps drop into the 10s and 20s. The GFS ensemble and other MREF forecasts are in close enough agreement with this storm for me to be pretty confident with this forecast.

The 18z GFS has also included a big storm into the Sunday forecast:



Do not be fooled, though. This run appears to be an outlier, as the GFS ensemble forecasts show the vast uncertainty that comes along with this second system. The ECMWF has quite a different solution, with the storm diving further south and making its way up north on Monday instead.



As you can see, there are very different solutions for this second storm, so much can't be said about it at this time. The main low could track west of the Appalachians, or hug the coast as it moves northward. There are also solutions that have no precip for NYS, so anything can happen at this point.

Sunday, February 22, 2009

NYS To Miss Another Big Storm Today

The models have been slowly pushing this storm further and further east. With the heavy precip just crossing over into eastern NYS, these small shifts mean big differences in certain parts of the state, such as my location in Albany.

Here are the 06z NAM and GFS runs from earlier today:



This correlates into about 2-4" of snow for the Albany area. I'm going with 1-3", since there is a possibility of some mixed precip during the storm if the surface warms up enough. Not a bad event, but it's peanuts compared to parts of northern New England, Maine in particular. Some areas are expected to get 12-18" of snow by the end of the storm tomorrow night, with localized areas of 18-24". Yeah...they can have that for all I care.

And of course there's going to be lake effect for those who live further west, but that's just a given.

Friday, February 20, 2009

NYS Remains Quiet... Southeast Gets Tornado Outbreak

Besides an inch of snow (which melted already) and some rain, the Wednesday/Thursday event was... uneventful for most of NYS. The southeastern states saw a tornado outbreak, recording the second EF4 of the season, along with the first EF3 and many smaller tornadoes.



The latest GFS runs are throwing in a Nor'easter into the New England states this Sunday, which will scrape the eastern parts of NYS. The NAM run has the main precip core a bit further east. The discrepancy is the secondary low forecasted to form just off the coast, which the GFS has forming and deepening sooner than the NAM. The NAM is in closer agreement with the European model than the GFS is, so I'm banking on the storm staying further east. Good news for us winter haters!

Tuesday, February 17, 2009

Storm To Bring Wintry Mix Into NYS Tomorrow

A storm that is gathering strength in the Central Plains states today, and will make its way northeast into NYS Wednesday afternoon and evening. The storm will begin as snow, and will likely transition over to rain in the valley regions during the overnight hours. Albany will be getting a nice southerly flow, which will help hinder the accumulation of snow. 1-3 inches of snow is expected to fall before the transition, which will make for slushy road conditions for the Thursday morning commute.

Periods of a rain/snow mix are also expected, but luckily sleet and freezing rain won't be a factor in this storm. The rain/snow showers are expected to taper off by Thursday afternoon, with scattered flurries Thursday evening and Friday. We will catch a short break before another system moves into the region, which will bring some small additional snow accumulations during the weekend, with 0 to 3 inches of snow falling across the state.

Tomorrow looks like the start of another dynamic pattern, in which NYS will get a storm every 2-3 days for at least the next couple of weeks. The storms over a week out from now appear to be mostly rain, but these storms are too far out to make any deterministic forecasts.

Thursday, February 12, 2009

Update On Severe Weather In The South, And NYS Weather

NYS missed out on severe storms last night, with the exception of one lone wind report, as the main line that produced well over 300 wind reports in the Southeast, Midwest and Mid-Atlantic states petered-out before entering NYS:

2/11/09


My prediction for a tornado outbreak on the 10th was confirmed by additional reports that came in yesterday after storm damage was analyzed in the southern Great Plains:



It just squeaked in as an outbreak, with the minimum of six tornado reports, but was an outbreak nonetheless. The wikipedia article on this event is a little contradictory, stating that there were seven tornadoes reported. Included is an EF4 wedge tornado, with unfortunately cut through the town of Lone Grove, Oklahoma, which has thus far killed at least 9 people, with about 50 others injured. A local news station, KOCO, has video footage of an EF2 tornado taken from their news helicopter. The severe potential is minimal through the rest of the week, which is good news for those involved in the cleanup from these storms.

As this storm moves off the coast, NYS is left with near-normal temps, with lows in the teens and highs in the low to mid 30s. Today will remain windy, with scattered rain and snow showers as temps fall throughout the day. Expect drier conditions to dominate our weather from tomorrow until around mid-week next week. The latest model runs indicate a mixed-precip nor'easter, which could greatly affect NYS weather around Wednesday. I will keep an eye on this system, and report on it later this week as I get a better look as to how this storm will track.

UPDATE:
As reports and assessments continue to come into the NWS, the tornado count for February 10-11 is up to 11, with two more tornadoes occurring the next day.

Also updated to include the new wind report that popped up.

Sunday, February 8, 2009

National Severe Thunderstorm Season About To Get Underway

Severe weather is popping up in the forecasts! It's not up here in NYS yet, but we might see a little bit in the upcoming week.

For the short term, there is a slight risk of severe storms just east of the Rockies, mostly in western Texas. This storm has a VERY SLIGHT risk of producing tornadoes, but we'll likely just see some wind and hail reports from this system.

Day 1 Outlook (tornado: 2%, hail: 15%, wind: 15%):


What we're really watching is the storm that forms in the wake of this one, which is forecast to have a much higher potential of producing severe storms and tornadoes than the one that is currently forming. Day 3 brings a much higher risk of supercell thunderstorms and tornadoes, and it looks like this second system could produce our first tornado outbreak of the season. If not, then it certainly has the capacity to produce a lot of wind and hail reports. CAPE is going to be the make-or-break factor for the chance of tornadoes, which, at this point, is forecasted to max out around 500-700 J/kg, whereas environments more favorable to tornadoes have at least twice as much CAPE. If this storm can gather enough energy, it will become powerful indeed.

Day 3 Outlook (overall chance of severe weather):


This stronger storm is forcasted to move northeast from the Great Plains, and enter NYS early Thursday morning. However, this is still a reasonable amount of uncertainty with this storm as to where it will track. The "doomsday scenario" for NYS includes a brief period in the warm sector of this storm, which could give us the potential for severe weather before the storm moves out. The more likely scenario is that NYS just gets a few showers, with brief periods of moderate rain.

But one can always dream...

Tuesday, February 3, 2009

Could A Regime Change End The Cold Spell? ...And Research

Model runs are consistently showing the breakdown of a long-standing ridge over the western U.S. and eastern Pacific, which means that temps on the eastern half on the nation will warm up as the trough breaks down! Seasonal to above-average temps are expected in the coming days, which is good news for the snow haters out there (including myself).

As part of my own new regime, I plan on updating this site at least twice a week from now on. Perhaps it's time to get this thing really going.

As for my research, I have officially submitted it to the 34th Annual Northeastern Storm Conference. Below is the title and abstract for my paper. It is similar to the research I did last fall, except I've replaced the warm cases with control cases, which will strengthen the overall paper. I should be presenting this Saturday morning on March 7.


TITLE:

A Comparison Of Cold Season Non-severe Wind Storms
And Severe Wind Outbreaks In New York State


ABSTRACT:

This paper examines synoptic features associated with severe wind outbreaks in New York State (NY), and how they differ from similar outbreaks that produce strong, but mainly non-severe, winds. The differences between these events can be very subtle, but make a large impact as to whether or not the storms reach the 50 knot threshold needed to be considered severe. Being able to distinguish better between non-severe and severe wind events could help improve the accuracy and range of severe wind warnings in NY.

To determine synoptic features common to the severe wind outbreaks, three severe wind cases and three non-severe wind cases between 1 November and 21 March of the years 2005-2008 were analyzed to determine common synoptic-scale features using conventional upper air and surface data, as well as satellite and sounding data. A particular focus of the case studies was on the forcing for ascent, provided by vertical circulations associated with strong polar and subtropical jets. The sounding data also contained characteristic signatures, which help distinguish between non-severe winds and severe wind outbreaks. These common features could be used to potentially forecast future severe wind outbreaks in NY and adjacent areas.