The unnamed storm and the named storm

THE UNNAMED STORM

[Updates on Kyle and Jangmi are after original entry, followed by a comparison of the no-named storm and Subtropical Storm Laura.]

Meteorologists certainly don't agree on everything -- not only forecasts, but basic analyses too. We're all just trying to assess things as best as we can, and it's okay to have a healthy debate.

In that spirit, and recognizing that TWC and I don't make the official call on tropical cyclone classifications, it's time to put on my ombudsman hat, if you will, again ... like I did about Subtropical Storm Andrea last year (I thought it should have been named sooner); then Tropical Storm Erin (in the postseason evaluation it should have been classified as a tropical storm again in its bizarre phase of regeneration over Oklahoma); Hurricane Noel (was not "extratropical" when it struck Cape Cod and Nova Scotia); and Tropical Storm Olga (should have, at least in the postseason evaluation if not in realtime been classified as a tropical storm again).

Now, there's the case of the unnamed storm which affected the East Coast on Wednesday and Thursday. It produced winds strong enough to cause power outages in the Tidewater area; coastal flooding in some locations from there to the Outer Banks to Charleston, South Carolina; beach erosion; and locally heavy rain.

This system was analagous to Andrea in 2007, starting out decidedly non-tropical (extratropical), with a frontal system and a strong pressure gradient (albeit not as strong as pre-Andrea's) between it and a high pressure system to the north. Then on Thursday it changed character.

The pressure gradient and wind distribution changed, with one zone pushing north and detaching, leaving a more concentrated area of stronger winds around the center of the cyclone. This was a model's analysis, which appeared to be pretty accurate.

[Image source: Wright-Weather, LLC]

The storm also changed its appearance on satellite and radar, with clouds and showers and thunderstorms spiraling around the center, and the pressure dropped to 991 millibars (29.26").

[Image source: NASA Earth Science Office]

[Image source: GRLevelX]

And there were recon measurements such as these.

I. 12 C / 1511 m
J. 19 C / 1525 m

Translation: the temperature at flight level (~1500 meters, or nearly a mile altitude) was 7 degrees C (19 vs 12) warmer in the center of the cyclone than outside the center. That means that throughout a portion of the atmosphere the storm was "warm-core," an additional sign that it was taking on tropical characteristics. Other analyses suggest that the storm was probably cold-core higher up, indicating that the storm was a tropical/non-tropical hybrid.

Nowadays names are given to both tropical and subtropical storms in the Atlantic. The meteorological reason officially given for not naming this one was that it was still attached to a front. That has generally been the case throughout the past couple of days (although at times such fronts have been less well-defined). Cool, dry air involved in the storm's circulation was another indication that it was not completely tropical. Again, it was a hybrid. Such hybrids come in different varieties, and this was one: it should have been a named subtropical storm. (For more on what constitutes a subtropical storm, see my entry on Andrea last year).

But any way you slice it, lemme tell ya, totally non-tropical cyclones don't look like this (radar image from this afternoon) after forming in the subtropics, making landfall, and moving inland!

[Image source: WeatherTAP]

There may have been a non-meteorological reason for not naming it after its transition to a subtropical storm, which is that many of the more significant impacts had already occurred, and it might have sent a confusing message to then suddenly have a name, gale warnings changed to tropical storm warnings, etc. This brings back memories of the Perfect Storm, which was a monster (much more severe than yesterday's, and it was a hybrid too!) which then had a small hurricane develop at the end of the main storm's life, and a decision was made to not designate it as a hurricane with a name since it was not expected to bring impacts rivaling the previous ones.

So it's easy to have mixed feelings. On the one hand, the effects of yesterday's storm were the same either way (it's not like it became totally tropical, rapidly intensified, and brought much stronger winds and a higher surge). And ultimately, isn't all this just an academic exercise for meteorologists to discuss amongst themselves?

On the other hand, names do draw attention to the weather situation, and if we're gonna have criteria and definitions and things like that, then oughtn't we adhere to them? Either that or go back to the way things were when cyclones were only classified as unnamed non-tropical ones or named tropical ones?

THE NAMED STORM

Speaking of the Perfect Storm, Lilapsophile posted a comment to my initial entry on the current set of weather systems asking whether the two could interact a la what happened in late October 1991. For awhile some computer model runs were indeed showing something along those lines, and there was some wiggy stuff out there on the web and in computer model land showing worst-case scenarios for New York City and thereabouts.

However, for events like the Perfect Storm, stuff has to happen so, uh, perfectly that they are rare events. Ditto hurricane landfalls in NYC or the Jersey Shore, and those don't happen very often even on Long Island.

The type of weather pattern we've had this week is one which can produce such an outcome, with an upper-level low over the southeast U.S. and a blocking ridge over the North Atlantic, with a chute in between through which a tropical cyclone can travel toward the NW, and/or some wild interaction can occur between multiple weather systems.

The unnamed storm did move northwest, and the overall setup that does include both its remnants and the storm which did get a name (Kyle) is creating an influx of tropical moisture that is leading to ongoing heavy rain and potential flooding in the Northeast ... but the model fantasies of earlier this week are not coming to pass.

Close, as they say, counts in horseshoes (and a couple of other things) but not in this case. If everything would have come together just a little differently the outcome could have been much different, but it didn't and it wasn't.

Kyle is still present, though, and as with all tropical cyclones there are certainties and uncertainties. What we're sure of is that it's going to get caught up in the flow pattern and move generally north, with a limit to how strong it can get. The uncertainties include exactly what its intensity will be and its precise track.

The storm has been disorganized and really struggling intensity-wise, as upper-level shear is pushing all the "convective" action to the east and has, at times today, left the center naked to the world.

Though it might win for awhile, and becoming a hurricane can't be ruled out, the storm is going to have to continue to fight those sorts of hostile environmental conditions throughout its lifetime.

For Kyle to have a very significant impact in New England, and not just give a relatively mild brush, it'd have to strengthen quite a bit, become more symmetric, and take a track west of what's currently expected. The stronger east side is more likely to affect Nova Scotia and/or New Brunswick, but this storm fortunately has a ways to go to rival how big and strong Noel was last year.

I'll post addenda with any significant updates ...

------------

Here's an addendum, as of 1 am EDT Saturday.

First, to answer laura's comment: yes, for a good part of its existence, the East Coast system was a nor'easter, since nor'easters are non-tropical storms characterized by strong onshore winds blowing from a northeast direction, as was the case with this one. For more on what a nor'easter is, see my entry from back in '05 on the subject.

Meanwhile, check out this satellite image, which helps keep Kyle (and the unnamed nor'easter / subtropical storm) in perspective ...

[Click on image for larger version.]

Notice a bit of a difference between it and the other satellite images in this entry?

It's of Jangmi, a super typhoon. "Super" typhoons are defined as having winds of 150 mph or higher, equivalent to high-end Category 4 or Category 5 hurricanes. Jangmi is unfortunately headed toward land; the Joint Typhoon Warning Center is forecasting a landfall in Tawain within the next 24-36 hours, with some decrease in intensity beforehand but still as a dangerous typhoon.

UPDATE 8AM EDT SAT

[Image source: NOAA]

These are the players this morning:

--Remnants of the unnamed storm along with an upper-level trough of low pressure over the southern Appalachians.

--A strong ridge of high pressure over the western North Atlantic.

--Kyle (red circle) in between, headed up the chute between the low and the high.

--A couple areas of moisture (green circles), one bringing heavy showers and thunderstorms from near Baltimore across east-central PA and central NY state, and the other lurking offshore and poised to enhance rainfall in New England regardless of the details of what Kyle does.

As for those details, in regard to the things I mentioned in the original entry, the storm has not significantly strengthened and become a hurricane (yet), and it is still rather assymetric, but the trend of the track is if anything a bit farther west, not east. The most likely path would take the center brushing by to the east of Cape Cod Sunday afternoon and making landfall not far from the U.S./Canada border at night.

So as far as New England is concerned, this ain't the 1938 hurricane, and the wind and ocean effects will even be less than many a nor'easter, but there will be locally heavy rain, and along the coast gusty winds and high surf.

UPDATE 4:45 PM EDT SAT

Kyle has now been officially upgraded to hurricane status (just barely so, though), and not only has Jangmi not yet shown signs of weakening, it is more fearsome than ever ...

[Image source: Naval Research Laboratory, NASA MODIS]

UPDATE 11 PM SAT SEP 27

JANGMI

The above is a water vapor image; here's a "visible" one from around the time that Jangmi was at its peak intensity:

[Image source: NRL; click on image for non-cropped version.]

Aircraft reconnaissance flights aren't routinely flown into western Pacific typhoons nowadays, but there was a "T-PARC" research mission flown into Jangmi, and it measured a pressure which had plunged down to 906 millibars (26.75") . For perspective, that's just a few millibars shy of Katrina's when that hurricane was at its most intense Category 5 strength over the Gulf of Mexico the afternoon prior to landfall, and apparently there were some other estimates in Jangmi a bit lower than 906. Also note the stunning description in the final remark in the observation below.

The report from Saturday afternoon local time (early Sat am ET), about an hour after the satellite image above, lists a maximum flight level wind of 163 kts (188 mph); the graphic below from the T-PARC operational website indicates a wind of 180 kts (207 mph) measured by a dropsonde a few thousand feet above the surface in the northwest eyewall.

The good news is that recent satellite images indicate that Jangmi is now slightly less intense than it was, but it's still very dangerous and capable of severe impacts as it bears down on Taiwan.

URPA12 PGUA 270755
VORTEX DATA MESSAGE
A. 27/07:55:30Z
B. 20 deg 58 min N
125 deg 05 min E
C. 700 mb 2294 m
D. 118 kt
E. 135 deg 10 nm
F. 237 deg 136 kt
G. 137 deg 11 nm
H. 906 mb
I. 12 C / 3049 m
J. 24 C / 3043 m
K. 9 C / NA
L. CLOSED
M. C18
N. 12345 / 7
O. 0.02 / 1.5 nm
P. AF306 0747W JANGMI OB 28
MAX FL WIND 163 KT E QUAD 06:16:40Z
SFC CNTR 360 / 4 NM FROM FL CNTR
WELL DEVELOPED EYE, FULL STADIUM EFFECT VISIBLE WITH SEVERAL STRAITIONS IN EYEWALL CLOUDS RUNNING DIAGONALLY ALONG WALL SURFACE FROM TOP TO BASE.

[Click on image for full version which also shows the exceptional warmth aloft in the eye.]

KYLE

The line of cirrus clouds extending from the lower-left portion of the image toward Kyle represents a dagger of hostility preventing it from strengthening much more, with strong upper-level winds blowing the deep convection (rain clouds and thunderstorms) onto mainly one side of the hurricane (unlike is the case with Jangmi), and a brisk flow throughout the atmosphere is accelerating the motion of Kyle toward the north.

The water vapor satellite image also shows a broad swath of deep tropical moisture out ahead of Kyle, which often happens with East Coast hurricanes, and the radar image below shows that it is manifesting itself via waves of heavy rain going over the same region, leading to a bunch of reports of local flooding coming in from eastern New England (including at the campsite noted by Keith in a comment).

UPDATE 2PM EDT SUNDAY

Jangmi did weaken a bit further prior to landfall -- the last Joint Typhoon Warning Center advisory before reaching the coast of Taiwan had it as the equivalent of a borderline Category 3/4 hurricane -- but that's still very powerful, and damage reports are starting to come in on the wires.

Kyle's band of heavy rain in New England dissipated overnight, but others have formed and are beginning to affect Down East Maine. That's where and what the main U.S. impact is expected to be, as the center approaches Nova Scotia this evening. There'll also be gusty winds and high surf on the U.S. side of the border, but the strongest winds and biggest waves will be in Canada.

Interestingly, the National Hurricane Center upped the official intensity this morning, but Kyle is expected to weaken later today and tonight.

Meanwhile, it appears yet another transition to a subtropical cyclone may be occurring, in a system to the east of Kyle in the Atlantic, and there's stuff around the Yucatan that bears watching for low pressure development in the eastern Gulf tomorrow and Tuesday.

UPDATE 3PM EDT SUN

Significant wave heights (avg. of the highest third) peaked at 36 feet at the Georges Bank buoy about 200 miles east of Hyannis. Maximum sustained winds there peaked at 60 mph, but that's a 10-minute 5-meter observation, which equates to about 72 mph for the standard of 1 minute and 10 meters. The peak gust at 5 meters was 80 mph.

UPDATE 12:15AM MON

[Image source: Naval Research Laboratory.]

Although the surface map shows not much in the way of temperature contrasts, fronts, etc., the satellite signature is, unlike the other day as the unnamed storm made landfall, squarely that of an extratropical (non-tropical) storm, and the National Hurricane Center has declared Kyle as such. Kyle left up to 7" of rain in Maine and here is the initial report of its effects in Nova Scotia:

>>>
Intermediate information statement issued by the Canadian Hurricane centre of Environment Canada at 12.00 midnight ADT Sunday 28 September 2008.

At 9:00 PM ADT.. Kyle came ashore just north of Yarmouth as a marginal category 1 hurricane. Hurricane force wind gusts of 124 km/h were reported at Baccaro Point in Shelburne County. The Weather Centre in Halifax has also received a report Of winds gusting to 154 km/h from a coast guard ship just off The Shelburne coast.

News has been received of trees downed in the tricounty area of Nova Scotia and of a boat swamped in a harbour in Shelburne County. Power outages are noted across various Locations in southern Nova Scotia. With arrival of dawn on Monday.. The extent of damage from Kyle will be better known.
>>>

(124 km/h = 77 mph and 154 km/hr = 96 mph; the anemometer height on the ship is not stated.)

Note the blip on the satellite image above in New Jersey. That's what's left of thunderstorms at least partially associated with the remnants of the ol' unnamed storm (remember that?), which caused flash flooding in some places in Pennsylvania on Sunday.

So, there was that in PA/NJ, and 7" in Maine. But Reuters is reporting that Jangmi unleashed up to 44" of rain in Tawian.

UPDATE NOON EDT MON

The system over the Atlantic has indeed been officially classified as a subtropical storm and given a name (Laura).

Here are satellite images of Laura and of the noname, allegedly non-tropical, storm.

Hmmm ...

[Source of images: NASA Earth Science Office]