March brings in week of great contrasts, typical of a transition into spring. Periods of rain off and on today before a plunge in temperatures going into Tuesday. Strong northwesterly winds will accompany the cold as the pressure gradient tightens around the departing low bringing rain today. Temps rebound into the upper-40s midweek but drop back towards end of week into the upper-30s.
Rest of today – periods of rain mostly before noon. Breezy with northwest winds increasing into the 15-20 mph by later in the day. Temperatures start dropping with these winds kicking in after noon bringing on strong cold air advection. Clouds clear towards the overnight when lows are expected to drop into low-20s.
GFS model 2-meter above ground level temperatures, and 10-meter above ground level winds at 7AM Tuedsay.
Tuesday – mostly sunny with high temperatures in the mid-30s. Strong northwest winds in the 20-30 mph range with gusts above 45 mph possible. Overnight lows in the low-30s.
Wednesday – high temperatures rebound quickly to near 50ºF with winds subsiding and mostly sunny skies. Overnight temperatures dropping into the mid-30s.
GFS model surface precipitation, and 1000-500 mb thickness for Thursday at 11AM. The blue thickness lines over much of the northeast indicate a return to below normal temperatures on the way.
Thursday– temperatures cooling a touch back into the mid-40s with mostly sunny skies. Overnight lows dropping back into the upper-20s.
A powerful storm tracking over the Great Lakes that brought a deadly outbreak of severe weather and strong tornadoes to the Deep South will continue tracking northeast over the Great Lakes. A warm front and cold front associated with this storm could bring thunderstorms, though regardless, dangerously strong winds will be present. After this storm passes, this gives way to a cooling pattern with a second, weaker storm coming Wednesday. Temperatures during this period start above normal in the 60s to below normal in the low-50s.
Rest of today – a powerful surface low over tracking over the Great Lakes with minimum central pressure below 984 mb will bring a period of dangerous winds to the region. The pressure gradient between this low and high pressure over the Atlantic will be very tight, as you can see below. This will result in sustained winds easily in the 30 mph range, with stronger gusts of 60-65 mph possible due to the very strong winds aloft. Both the warm front and cold fronts of this storm could touch off some isolated elevated thunderstorms, though instability will be modest at best. High temperatures should peak in the upper-60s with robust warm air advection due to these strong winds eventually turning southwest. Overnight lows in the mid-40s as this storm pulls away.
Weather Prediction Center surface forecast for 2PM Monday
Tuesday – skies clear up overnight into the morning. Partly cloudy to mostly sunny skies should prevail with high pressure building. High temperatures in the upper-50s. Overnight lows around 40°F.
Wednesday – a second, weaker low is forecast to form over the northern Gulf of Mexico along the southerly extremes of the cold front from this first storm. This low then slides northeast along the coast. Although this second storm will pass far to the south of us, it could still bring some rain during the day. With clouds, rain, and an onshore northeasterly/easterly flow, temperatures will struggle to hit 50ºF. Overnight lows in the upper-30s.
GFS model 500 mb height anomalies for 2PM Thursday. Negative height anomalies at the 500 mb level can often translate to below normal temperatures at the surface.
Thursday– temperatures remain cool despite more sun, only reaching into the low-50s. Overnight lows around 40ºF.
We start this weekend with a high wind warning as a strong low pressure center passing overhead. A much colder air mass will be on the heels of this passing storm. A brief calm Saturday spell punctuates an otherwise active pattern with another storm approaching to start next week. High temperatures during this time will generally be at or above normal (~40°F) with a big warmup by Monday.
Rest of today – high temperatures have already peaked in the mid-50s but the remainder of the day will see a continuing fall in temperatures through the 40s and 30s as strong cold air advection kicks in. This is due to a potent low pressure system (972 mb and strengthening) passing overhead. The tight pressure gradient around this low, in addition to a well-mixed layer forming with winds aloft at 50 knots mixing down will yield very strong winds. A high wind warning is in effect this afternoon when sustained winds could easily be in the 30-40 mph range with gusts exceeding 60 mph in places. Winds will abate overnight as the low exits northeast, temperatures will keep falling all the way into the upper-20s with cold air advection driven by winds from the northwest continuing.
Weather Prediction Center surface forecast for 1 PM today. Note the tight packing of isobars around the 972 mb low pressure center moving just north of the area.
NAM model’s forecast sounding for 1PM today. Very strong unidirectional wind profile is indicated, with winds just above the surface in excess of 50 knots. A well-mixed layer is evident as well up to about 850 mb where winds look to range between 55-65 knots. This should allow strong gusts and sustained winds to make it to the surface.
Saturday – high pressure builds in briefly, and should yield a mostly sunny day. With overnight lows in the upper-20s, high temperatures will be decidedly colder around 40°F. Overnight lows remain on the cold side around 30°F.
Sunday – clouds increase with high temperatures in low-40s as the next frontal system approaches. Winds will shift to the south. There is a chance for rain/snow mix then rain during the day. Overnight lows in the mid-30s.
Monday– prolonged southerly flow will help kick temperatures up to the low-50s as the frontal system slows in its approach. This will also bring prolonged chances for rain. Overnight lows in the upper-30s.
In lieu of an early week forecast this week, I’m opting to share some observations about weather I experienced in Mexico last week while on vacation. I stayed in Isla Mujeres, a small island located about 13 miles off the coast of Cancun. Temperatures were of course quite warm. It was also unusually windy for this time of year down there, though nothing quite like the windy weather NYC experienced today with some peak winds recorded at over 50 mph nearing 60 mph.
METAR READINGS FROM JFK and LGA showing peak winds of 56 mph and 58 mph respectively recorded at 12:04AM and 8:31AM respectively todaY
I’m only just getting adjusted back to cold temperatures, and am not looking forward to snow possibly falling Wednesday night and another storm bringing wintry precipitation Friday. On the bright side, we are now only about 3 weeks off from the vernal equinox and the start of spring!
On the Servicio Meteorológico Nacional (SMN) – National Meterological Service of Mexico
Since I was going to be in Mexico, I started checking out the Mexican government’s weather service page. Check out the surface analysis below that’s overlaid on what looks like a GOES East image from last Thursday (02/21/2019).
Click to enlarge this surface analysis from the Mexican SMN
Unlike our own National Weather Service, the SMN numbers frontal systems that move through Mexico. Notice the stationary front in the center of the image is labeled as “Frente No. 38” (Front #38) and you can see “Frente Frio No. 40” (Cold Front #40) crossing from southern California into northern Baja California in the upper left corner of the image. They also number their winter storms. The “B” (representing a low pressure center) over Nevada is labeled as “Octava Tormenta Invernal” (Eighth Winter Storm). “Corriente en Chorro Polar” (polar jet stream), “Corriente en Chorro Subtropical” (subtropical jet stream) are familiar features to us, which we seen streaking across the northwest and central portions of Mexico respectively. A “Corriente de Bajo Nivel” (low-level jet) is seen flowing from the east towards the Yucatan. Here’s a translation of the text in the lower left panel:
Systems affecting Mexico The Eighth Winter Storm over the southwestern US combined with cold front #40 in northwestern Mexico will favor showers with some strong storms, very cold temperatures, and wind gusts over 60 km/h in the northwest and northern Republic, and also the potential for snow or sleet in mountainous areas of Baja California, Sonora, and Chihuahua, extending gradually towards Durango. Front #38 with stationary characteristics extends over the western Gulf of Mexico and will generate clouds with isolated rain in the eastern and northeastern parts of the country.
Servicio Meteorológico Nacional of mexico
Synotpic Conditions – the Tropical Big Picture
The consistent breezy south-southeasterly winds I felt on Isla Mujeres were tied to that low-level jet (LLJ) pictured above. This LLJ enhanced the general easterly trade winds in the area. This was a result of the influence of a high anchored over the Western Atlantic, and a low over northern Colombia pictured in the OPC surface analysis below (issued Friday 2/22 02:35Z) “funneling” the winds.
In this analysis of the Western Atlantic from NOAA’s Ocean Prediction Center, you can see that a broad high pressure center was anchored near Bermuda. Meanwhile, a low sat over northern Colombia. The clockwise flow around the high and counterclockwise flow around the low in proximity to each other act to enhance the easterly trade winds found in the tropics.
A
sounding from Philip Goldson International Airport near Belize City
(the closest sounding station I could find to Cancun) showed clear
evidence of a well-mixed layer from the surface to just about 900 mb. It
felt like in Cancun, this mixed layer extended a bit further up into
the 850 mb level where the LLJ sat because the winds were stronger.
Sounding taken above Philip Goldson International Airport near Belize City at 7PM Feb. 20, 2019, showing a well-mixed boundary layer representative of the area around the Yucatan Peninsula during these few days
By
way of brief explanation, well-mixed layers like the one shown above
provide favorable conditions for faster moving winds aloft to transfer
their momemtum downwards, in this case all the way to the surface. It
shouldn’t be a surprise that a deep well-mixed layer also existed today
over NYC – enabling the strong winds aloft to mix down, leading to some
very strong winds and gusts.
Sounding from Upton, NY for at 7AM Feb. 25, 2019, showing a deep well-mixed layer down to the surface from around 800 mb with strong winds 35-50 knots through most of this layer
Aside
from the winds, the weather followed a pretty standard tropical pattern
with clouds building in the afternoon and isolated showers. Despite how
flat the Yucatan Peninusla is, it nevertheless provides at least some
small potential for lift and convergence for air flowing off the
Caribbean Sea. This is because there’s actually a significant difference
in frictional properties of land and water, which makes sense since the
surface of the ocean is considerably “smoother” than the corresponding
forested Yucatan. One other notable trait was that the base of rain
clouds in the area took on a distinctively blue hue, which I imagine was
a reflection of the characteristically blue waters of the Caribbean
Sea.
Main weather headline to start the week will be a potent and slow-moving coastal storm bringing a variety of hazards to the region later today through tomorrow morning. This storm is the same one responsible for this weekend’s deadly tornado outbreak down south. Conditions improve dramatically towards mid-week.
Rest of today – a flood watch, coastal flood advisories, and high wind warning are in effect mostly through tomorrow morning. Cloudy with high temperatures steady around 40°F. Winds continue to increase throughout the day as a strengthening coastal low approaches and the pressure gradient between it and a high pressure center over Quebec tightens. A low-level jet will enhance winds. Sustained east and northeast winds of 30-40mph with gusts between 50-60mph will become commonplace late today and overnight. The strongest winds will occur closest to the coast.
Along with the strong winds, periods of heavy rain will bring the potential for 1-3″ of precipitation, which could lead to minor to moderate urban and small stream flooding. Timing of the onset of rain will be around 3pm this afternoon.
The persistent and strong northeast winds off the water will contribute to minor to moderate coastal flooding. This will be exacerbated during a couple of high tide cycles.
High resolution rapid refresh model simulated radar output for 3PM this afternoon
The storm approaching spans the better portion of the entire East Coast
Tuesday – rain and wind abate during the day, tapering off by the afternoon. High temperatures about the same as today in the low-40s.
Wednesday – as the coastal storm continues to pull away, temperatures rebound and mostly sunny skies return. High temperatures anticipated around 50ºF.
Thursday – another nice day with high temperatures in the upper-40s and mostly sunny skies.
