Dr. Masters cofounded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 19861990. Coblogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 1:51 PM GMT on February 06, 2012
Our calendars may say it's February, but Mother Nature's calendar says it's more like May in the waters of South Florida, where the year's first significant tropical disturbance is drenching the Keys. The disturbance, designated Invest 90L by NHC late Sunday morning, has dumped 1  3 inches of rain over much of the Florida Keys this morning, with Key West receiving 4.34" of rain on Sunday, a record for the date. The storm was close to developing a surface circulation last night, thanks to wind shear values to fell to 20  25 knots, and NHC gave 90L a 30% chance of developing into a subtropical depression in a special Tropical Weather Outlook issued last night. However, wind shear has increased to a prohibitive 30  40 knots this morning, and 90L is looking much less organized. In their 7 am EST outlook this morning, NHC gave 90L a 0% chance of developing. The system will continue to grow less organized today as it moves over Nassau in the Bahamas and heads out to sea.
Figure 1. Radarestimated rainfall from Invest 90L.
What's going on?
Obviously, strong tropical disturbances capable of developing into named storms are very rare in February, and I've never seen one in my 30 years as a meteorologist. However, ocean temperatures are warm enough yearround to support a tropical storm in the waters of the Western Caribbean. Water temperatures today in the region were 26  26.5°C (79  80°F), which is near average for this time of year. If an unusual configuration of the jet stream allows wind shear to drop below about 25 knots in the Western Caribbean, there is the opportunity for a rare offseason tropical storm to form in February. I discussed in an appearance on NPR's All Things Considered on Friday just how unusual the atmospheric flow patterns have been this winter, and today's rare tropical disturbance over South Florida is symptomatic of how whackedout our 2012 atmosphere has been. In isolation, the strange winter weather of 2011  2012 could be a natural rare occurrence, but there have been way too many strange atmospheric events in the past two years for them all to be simply an unusually long run of natural extremes. Something is definitely up with the weather, and it is clear to me that over the past two years, the climate has shifted to a new state capable of delivering rare and unprecedented weather events. Human emissions of heattrapping gases like carbon dioxide are the most likely cause of such a shift in the climate, as I discussed in my post last week, Where is the climate headed?
A historical precedent: the 1952 Groundhog's Day tropical storm
There is a historical precedent for a tropical storm this time of yearthe 1952 Groundhog's Day tropical storm that hit Southwest Florida. According to Wikipedia,
The 1952 Groundhog Day Storm was the only Atlantic tropical cyclone on record in the month of February. First observed in the western Caribbean Sea on February 2, it moved rapidly throughout its duration and struck southwestern Florida within 24 hours of forming. In the state, the winds damaged some crops and power lines, but no serious damage was reported.
Meteorologist Andrew Hagen performed a reanalysis of all the tropical storms between 1944  1953 for his Ph.D. thesis, and looked in detail at the 1952 Groundhog Day's storm. He noted that it didn't look like a classic tropical storm, but it didn't look like an extratropical storm, either, and should stay in the database as the first named storm of 1952. In the old teletype files for February 1952, he found a February 2 message from the Cuban Weather Service that expressed some concern about possible tropical development between Cuba and Florida. NHC responded: "TROPICAL STORMS DO NOT FORM IN FEBRUARY."
Figure 2. February 2, 1952 teletype message from the Hurricane Center to the Cuban Weather Service, explaining that there couldn't possibly be a tropical storm in February. Image credit: Andrew Hagen.
Jeff Masters
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74 °F
Overcast

233. SPLbeater
lol
232. TropicalAnalystwx13
Nope.
National Weather Service Wilmington, NC.
231. j2008
230. SPLbeater
for NC? no...lol no....did you write that? *thinks hard*
229. TropicalAnalystwx13
but puppies don't whine and complain and argue about stupid stuff. They don't worry about how they look or talk back or anything. :P
228. chimera245
You're right, I needed to take the ray to the first x value OUTSIDE the range  not the last inside.
The algorithm therefore being take the ray out to (102,53)  move one to the left (101,53)  giving
m = (53  2) / 101
or 51 / 101
It has been 26 years since I last did maths formally lol.
227. SPLbeater
he hasnt hid from us for the last 4,378 years he been here..why hide now??
226. WxGeekVA
Puppy < Girls..... But girls like puppies so that is a plus.... Just trying to give some advice as someone 3 years ahead of you on the High School timeframe...lol
225. TropicalAnalystwx13
Actually...
"IF PCP LASTS INTO SAT NIGHT MAY HAVE CONCERN FOR MIXED PCP AS
TEMPS DROP TO NEAR FREEZING BUT DRY AIR SHOULD MAKE IT IN."
224. WxGeekVA
223. SPLbeater
well, so far i havin no problems. besides, i get to go outside in the early morning to play with the puppy. which actually turns out to a situation where i am trying to get my arm out of its mouth, keep her claws off me and search for safe ground LOL
222. Xyrus2000
The variable m is given as a range though, so it cannot have an upper bound of infinity since there are plenty of numbers between 1/2 and infinity that can yield integer values for y.
I agree though, there seems to be some missing criteria in the problem. My previous post showed the next highest fraction for m (assuming integer numerators and denominators) that guaranteed noninteger y's, but that isn't the maximum bound. The maximum bound (strictly keeping to integers) would be 100/101, as there is no x in 0 < x < 100 that would yield an integer y. Since 101 is a prime, there is no chance for a reduction to a lower denominator that otherwise potentially yield an integer when being multiplied by x.
221. hurricanehunter27
220. RTSplayer
The Domain, which is the values of X, are not dependent on the value of m, except to say that x and y cannot both be integers at the same time.
This:
is arbitrary and is not "the" solution, because all you did was plug in arbitrary numbers for x and y, and incorrectly claim that this must be the value of m.
all I have to do to prove your solution wrong is prove that there is at least one solution where m is greater than 50/99 on the domain for 0 < x <= 100, which I already proved there are an infinite number of them.
If you don't believe me, get a graphic calculator and plug it in, or ask a college mathematics professor.
The question, as worded, does not say what either of you think it says.
219. SPLbeater
218. hurricanehunter27
217. Neapolitan
216. TropicalAnalystwx13
LOL yeah.
215. WxGeekVA
I feel sorry for you dude.... You are missing the best part of your life....
214. SPLbeater
another good reason why i am homeschooled. i get better grades because i am not distracted by some cute girl. lol(used to happen ALOT)
213. Xyrus2000
50/99 wouldn't be a valid answer. If x is 99, then you wind up with (50/99)*99 = 50.
The first fraction to meet the criteria for m would be 51/101. This is guaranteed to give fractional results over the integer x range as 101 is a prime and greater than the specified range for x.
212. WxGeekVA
I'm only in Trig and I only have a C in the class.... Too busy messing with girls in the back row to pay much attention....LOL
211. SPLbeater
i hear they have a very good meteorlology class. and a good football team!!!
210. j2008
209. hurricanehunter27
50/99 is one of them.
208. TropicalAnalystwx13
207. RTSplayer
Like I said, problem must be worded wrong.
There's an infinite number of values for m which meet the criteria, and they range from 1/2 to infinity.
In what you wrote, "a" is never given a definition except that it is some value larger than m.
m = "pi raised to the googleplex power".
it will not hit a lattice point ANYWHERE except 0 = x, but since you defined 0 < x, that isn't a problem.
The only limit you placed on "a" is that it is greater than m, but wait...
m = "pi raised to the googleplex raised to the googleplex"
Also never hits a lattice point, etc.
This is the first week of Calculus 101...or maybe precalculus if you take it in high school.
m is a coefficient, which in this case is the slope.
But by the substitution rule, m could be anything. It could be a real number, it could be irrational, it could be another function, etc.
206. TropicalAnalystwx13
Yup, that's where I'm gonna try to go.
205. hurricanehunter27
204. j2008
203. hurricanehunter27
202. HadesGodWyvern (Mod)
Tropical Disturbance Advisory #3
SEVERE TROPICAL CYCLONE JASMINE (12F)
12:00 PM FST February 7 2012
=====================================
At 0:00 AM UTC, Severe Tropical Cyclone Jasmine, Category Three (955 hPa) located at 17.4S 163.0E has 10 minute sustained winds of 80 knots. The cyclone is reported as moving east southeast at 13 knots. Position poor based on multisatellite enhanced infrared imagery and peripheral surface reports.
Hurricane Force Winds
=====================
30 NM from the center
Storm Force Winds
==================
60 NM from the center
Gale Force Winds
=================
150 NM from the center in northeast quadrant
140 NM from the center in southeast quadrant
110 NM from the center in southwest quadrant
160 NM from the center in northwest quadrant
Overall organization has improved significantly over the past 6 hours with eye forming. System remains in a region of upper diffluence enhanced by a shortwave trough just to the west. Outflow remains good. Cyclone is being steered to the east southeast by strong westnorthwest steering and lies in an area of low vertical wind shear.
Dvorak analysis based on dg eye with lg surround
Dvorak Intensity: T5.0/5.0/D1.0/24 HRS
Models generally agree on an east southeastward movement in the next 24 hours.
Forecast and Intensity
=====================
12 HRS: 18.7S 165.6E  80 knots (CAT 3)
24 HRS: 19.6S 168.1E  75 knots (CAT 3)
48 HRS: 22.9S 171.6E  65 knots (CAT 3)
The next tropical disturbance advisory on Severe TC Jasmine from Fiji Meteorological Services will be issued at 8:30 AM UTC..
201. chimera245
I *think* I replied correctly with 50/99.
While it is true that given infinite x there will always be an intercept, the question was actually given:
0 < x <= 100
and
1/2 < m < ??
It's been a few years since A Level maths for me  but I'm fairly certain my argument is correct :)
200. hurricanehunter27
Read this if your interested to tired to explain. Link
199. SPLbeater
u shoulda googled it lol
NCSU WOLFPACK!!!!
198. RTSplayer
The question placed no conditions on the value of y, except that the line never passes through a lattice point, which is to say y and x cannot both be integers at the same time.
so, for example:
y = mx  2, 0 < x < 100, and (1 / 2) < m < a.
if m = pi, then no lattice point will ever be crossed for any x = / = 0, and m > 0.5.
And now, if we replace "m" with some function of pi, such as 2 * pi, 3 * pi, 4 * pi, etc, none of those will ever cross a lattice point either.
Infact, for n * pi as n approaches infinity, the line will also never cross any lattice point.
So a has no maximum limit except "infinity".
m does have a MINIMUM limit which is infinitesmally close to 1/2, but only because he defined 1 / 2 < m. A has a minimum limit infinitesmally close to m.
There are an infinite number of values for m which do not violate any of the conditions as they were given in the problem.
Edit:
Wow.
This site really doesn't handle basic mathematics symbols very well. HTML and scripting languages use the less than and greater than and slashes for tags and interupts and the script can't handle it.
P.S.
Your teacher/boss and your text book answer key can be wrong.
Happens all the time in college and at work.
197. HadesGodWyvern (Mod)
Tropical Disturbance Advisory #4
TROPICAL CYCLONE CYRIL (11F)
12:00 PM FST February 7 2012
===================================
A TROPICAL CYCLONE ALERT IS NOW IN FORCE FOR NIUE.
A STRONG WIND WARNING REMAINS IN FORCE FOR NIUE.
At 0:00 AM UTC, Tropical Cyclone Cyril, Category Two (985 hPa) located at 20.0S 171.9W has 10 minute sustained winds of 50 knots. The cyclone is reported as moving east southeast at 18 knots. Position fair based on hourly GMS enhanced infrared radar imagery and peripheral surface reports.
Storm Force Winds
===================
20 NM from the center
Gale Force Winds
===============
120 NM from the center in northeast quadrant
120 NM from the center in southeast quadrant
120 NM from the center in northwest quadrant
50 NM from the center in southwest quadrant
Organization has improved significantly past 24 hours. Convection increased with primary bands trying to trap around the low level circulation center. System lies south of 250 HPA ridge axis. Outflow good to the north and east. System lies in a low to moderate sheared environment and is being steered southeast by a northwest deep layer mean flow into an area of increasing shear. Sea surface temperature around 27C
Dvorak analysis based on 0.9 wrap
Dvorak Intensity: T3.5/3.5/D1.5/24 HRS
Global models move the system southeastward with decreasing intensification.
Forecast and Intensity
=======================
12 HRS: 22.2S 168.9W  45 knots (CAT 1)
24 HRS: 24.8S 165.0W  40 knots (CAT 1)
The next tropical disturbance advisory from Fiji Meteorological Services on TC Cyril will be issued at 8:30 AM UTC..
196. j2008
195. hurricanehunter27
194. WxGeekVA
Penn State, Miami (FL), Ohio State, Florida State, and Oklahoma.
193. hurricanehunter27
192. WxGeekVA
Junior.
191. hurricanehunter27
190. WxGeekVA
189. Neapolitan
188. pottery
No Problem.
Anytime!
:):))
187. hurricanehunter27
186. hurricanehunter27
185. chimera245
Starting with the slope at 0.5, you get intercepts at (2,3), (4,4), (6,5), generally up to ((n2)*2,n).
Given that your limit of x (n2)*2 is 100, then the largest one of these intercepts is where n = 52, i.e (100,52).
Moving m upwards moves the x value to the left, so our next intercept point would be (99,52)  this is the limit for m. Back substituting this point using:
m = (y  2) / x
Gives me
m = (52  2) / 99
or 50/99
So I get m < 50/99
Or am I missing something?
184. pottery
Looks to me like things are slow on this blog today.
Well, here is what is going on right here.
And IT AINT SLOW.....
183. RTSplayer
Ok, he wants the line to never pass through a lattice point between 0 < X < 100.
If m is rational and between 100 and 1/100, then the line will always pass through a lattice point, eventually.