Flash Floods in Hawaii

May 10th, 2011
MIMIC TPW over the eastern Pacific Ocean

MIMIC TPW over the eastern Pacific Ocean

Images of MIMIC Total Precipitable Water, above, show moist air emerging from the Intertropical Convergence Zone and streaming north over the western islands of Hawaii.

GOES Imager Water Vapor imagery

GOES Imager Water Vapor imagery

GOES-West water vapor imagery (the rocking animation, above) shows the circulation north of the Hawaiian islands that is drawing moisture northward. Because the water vapor channel on the Imager is most accurate at sensing the temperature at the top of the moist layer, however, water vapor imagery can significantly underestimate the amount of water vapor that is in the atmospheric column. The warm temperatures evident over the western Hawaiian Islands (the blue and yellow enhancements) suggest that the water vapor that is emitting radiation sensed by the satellite is warm and confined to lower levels in the atmosphere. Images of Total Precipitable Water give a better indication of how much water vapor is available for precipitation.

Flash flood watches continue through late Tuesday, 10 May, for the western Islands of Hawaii (Oahu, Kauai and Niihau) as the moisture plume continues to drift westward.

The CIMSS MIMIC Total Precipitable Water product is also available for NWS forecast offices to add to their local AWIPS workstations (via Unidata LDM subscription) — a sample animation is shown below. To learn more about the MIMIC TPW product and its applications, a VISIT lesson is also available.

 

MIMIC Total Precipitable Water product (click image to play animation)

MIMIC Total Precipitable Water product (click image to play animation)

Possible development of a subtropical or a tropical disturbance in the Atlantic Ocean?

April 20th, 2011
MIMIC Total Precipitable Water (TPW) product

MIMIC Total Precipitable Water (TPW) product

The National Hurricane Center initiated Invest 91 to monitor the potential development of a subtropical or even possibly a tropical cyclone over the western Atlantic Ocean on 20 April 2011. AWIPS images of the MIMIC Total Precipitable Water (TPW) product (above; click image to play animation) showed that a tongue of moisture was being advected northward from the band of higher moisture along the Inter-Tropical Convergence Zone (ITCZ) — and this moisture plume was being wrapped into the circulation of the developing disturbance.

A closer look at the MIMIC TPW product at 14:00 UTC along with an overlay of ASCAT scatterometer winds (below) revealed a well-defined cyclonic circulation at the surface, with gale force winds within the northwest quadrant of the storm.

MIMIC TPW product + ASCAT surface winds + Surface analysis

MIMIC TPW product + ASCAT surface winds + Surface analysis

===== 22 APRIL UPDATE =====

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

Animations of GOES-13 0.63 µm visible channel images (above) and GOES-13 10.7 µm IR channel images (below) from the CIMSS Tropical Cyclones site continued to show very well-defined cyclonic circulations associated with the feature on 22 April 2011.

GOES-13 10.7 µm IR images

GOES-13 10.7 µm IR images

GOES-13 6.5 µm water vapor channel images (below) indicated that dry mid-tropospheric air was wrapping into the system from the south and east.

GOES-13 6.5 µm water vapor channel images

GOES-13 6.5 µm water vapor channel images

A comparison of AWIPS images of the POES AVHRR 0.86 µm visible channel with ASCAT scatterometer surface wind data (below) revealed the development of deep convective elements just to the north of the low-level circulation center.

POES AVHRR 0.86 µm visible image + ASCAT scatterometer surface winds

POES AVHRR 0.86 µm visible image + ASCAT scatterometer surface winds

A sequence of three POES AVHRR 0.86 µm visible channel images (below) showed the evolution of the convective elements associated with the disturbance during the day.

POES AVHRR 0.66 µm visible channel images

POES AVHRR 0.66 µm visible channel images

35-year anniversary of the sinking of the Edmund Fitzgerald

November 10th, 2010
48-hour simulated IR satellite imagery from the CRAS model (9-11 Nov 1975)

48-hour simulated IR satellite imagery from the CRAS model (9-11 Nov 1975)

Today marks the 35-year anniversary of the powerful Great Lakes storm that was responsible for the sinking of the SS Edmund Fitzgerald (on 10 November 1975). Since the first operational geostationary weather satellites (SMS-1 and SMS-2) were relatively new back in 1975, the CIMSS Regional Assimilation System (CRAS) model was utilized to generate synthetic IR satellite images to provide an idea of what the satellite imagery might have looked like for this intense storm (CRAS model surface winds). A 48-hour sequence of synthetic IR images (above) shows the evolution of the model-derived cloud features at 1-hour intervals.

As part of the CIMSS involvement in GOES-R Proving Ground activities, CRAS synthetic forecast satellite imagery (IR and Water Vapor channels, below) is currently being made available in an AWIPS format for interested NWS forecast offices to add to their local AWIPS workstations (via LDM subscription). For more information, see the CRAS Imagery in D-2D site. VISIT training is also available on the topic.

CRAS forecast IR imagery in AWIPS

CRAS forecast IR imagery in AWIPS

CRAS forecast water vapor imagery in AWIPS

CRAS forecast water vapor imagery in AWIPS

Super Typhoon Megi

October 18th, 2010
MTSAT-1R 0.68 µm visible channel images

MTSAT-1R 0.68 µm visible channel images

MTSAT-1R 0.68 µm visible channel images (above) tracked the eye of Super Typhoon Megi making landfall across the northern portion of the island of Luzon in the Philippines on 17-18 October 2010.

The Morphed Integrated Microwave Imagery at CIMSS (MIMIC) product (below) showed the well-defined eye of Megi prior to making landfall, along with the effect that the rugged terrain of Luzon had on the typhoon before it later emerged into the South China Sea.

Morphed Integrated Microwave Imagery at CIMSS (MIMIC)

Morphed Integrated Microwave Imagery at CIMSS (MIMIC)

A Terra MODIS 11.0 µm IR image (below; zoomed-in version) revealed the eye and surrounding concentric eyewall structure of Megi at 02:30 UTC on 19 October — the coldest IR brightness temperature seen at that time was -82º C (purple color enhancement) to the south of the eye.

Terra MODIS 11.0 µm IR image

Terra MODIS 11.0 µm IR image